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Title: SLCO1B3 gene alterations and protein expression in colorectal cancer Authors: Lampri Evangeli1, Sainis Ioannis1, Kounnis Valentinos1,, Mitselou Antigony2, Ioachim Elli3, Hatzimichael Eleftheria1,4, Galani Vasiliki 5, Briasoulis Evangelos1,4 1 Cancer Biobank Center, University of Ioannina, Ioannina, Greece 2 Department of Forensic Pathology, University of Ioannina, Ioannina, Greece 3 Department of Pathology, General Hospital “G.Hatzikosta”, Ioannina, Greece 4 Department of Hematology, Ioannina University Medical School, Ioannina 5 Departments of Embryology-Histology-Anatomy, University of Ioannina, Ioannina, Greece Correspondence to: Lampri Evangeli, MD, University of Ioannina Cancer Biobank Center, Post code 45500, Ioannina, Greece , Phone: 0030-265-10-07713, [email protected] The research was performed in University of Ioannina Cancer Biobank Center, iMOL, Post code 45500, Ioannina, Greece Short running title: A study of SLCO1B3 in colorectal cancer Authors details: Lampri Evangeli, MD, Msc, PhD, University of Ioannina Cancer Biobank Center, iMOL, Post code 45110, Ioannina, Greece , Phone: +30-265-10-07713, [email protected] (corresponding author) Sainis Ioannis, PhD, University of Ioannina Cancer Biobank Center, iMOL, Post code 45500, Ioannina, Greece , Phone: +30-265-10-07713, [email protected] Kounnis Valentinos, PhD, MD, Hypoxia and Angiogenesis Group, Molecular Oncology Laboratories,Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, OX3 9DS, Oxford, UK, Phone: +44-1865-2-22440, [email protected] Mitselou Antigony, PhD, MD, University of Ioannina, Department of Forensic Pathology Post code 45110, Ioannina, Greece, [email protected] Ioachim Elli, PhD, MD, Department of Pathology, General Hospital “G.Hatzikosta”, Ioannina, Greece, [email protected] Hatzimichael Eleftheria PhD, MD, University of Ioannina Cancer Biobank Center, iMOL, Post code 45500, Ioannina, Greece, Phone: +30-265-10-07713, [email protected] Galani Vasiliki, MD, PhD University of Ioannina Departments of Embryology-Histology-Anatomy, University of Ioannina, Ioannina, Greece, [email protected] Briasoulis Evangelos, Professor, University of Ioannina Cancer Biobank Center, Post code 45110, Ioannina, Greece, Phone: +30-265-10-07713, [email protected] Abstract Background: Personalized medicine has made some major advances in Colorectal cancer (CRC), but new biomarkers still remain a hot issue as an emergingtool with potential prognostic and therapeutic potential.We ivestigated for SLCO1B3 gene alterations and protein expression in colorectal cancer, using the novel High Resolution Melting analysis (HRMA) technique and immunohistochemistry. Materials and Methods: Formalin-Fixed paraffin-embedded tumor samples from 30 colorectal cancer patients were used. The screening for gene alterations was done by High Resolution Melting analysis (HRMA) for all exons of SLCO1B3. OATP1B3 protein expression was assessed by immunohistochemistry using the monoclonal mouse MDQ antibody. Results: High level of polymorphism was observed in the SLCO1B3 gene. We identified three previously reported polymorphisms in exons 7, 12 and 14, 699G>A, 1557 A>G and 1833G>A, respectively. In the exon 5, one variant seems to correspond to an as yet unknown SLCO family member. The immunohistochemical study revealed that OATP1B3 was expressed in 27/30 samples. Of great interest, the three samples, which were immunohistochemically negative, all appeared to accommodate mutations which lead either to early stop codons or other conformations of the tertiary protein structures affecting the antibody- epitope binding. Conclusions: The results of this study are of much interest as HRMA proved to be a reliable and rapid genotyping/scanning method for mutation detection of SLCO1B3. Introduction Colorectal cancer (CRC) is major world health issue because of its high prevalence and mortality rates. It consists the second most common cancer diagnosed in Europe and the third most common cancer in the US[1, 2, 3]. This cancer although highly curable by surgical resection at early stages, when it presents with metastases at diagnosis, which occurs in 25% of the patients, or when it becomes metastatic, which happens in 50% of the cases, it is considered largely incurable, despite the progress made in the development of novel therapeutics [3]. Therefore, the discovery of novel molecular targets and targeted therapies is of major importance for an essential improvement of therapeutic outlook in this large group of patients. SLCO1B3 belongs to solute carrier organic anion transporter family and encodes the human organic anion-transporting polypeptide (OATP) 1B3 [4]. It is located in chromosome 12 (2p12–31.7 to 12p12–37.2) (Figure 1A.) [5]. This gene has 6 transcripts, two of which, SLCO1B3-001 and SLCO1B3-201, have a Consensus CDS and comprise of 16 and 15 exons, respectively [6], their main difference is in the 1st and 2nd exon of the 001 transcript. (Figure 1B). OATP1B3 seems to be the only hepatic OATP transporting digoxin, amanitin, docetaxel and paclitaxel. In addition, OATP1B3 expression has been suggested as a potential variable of tumour sensitivity to methotrexate treatment [7-15]. Moreover, besides the abundant expression in the periportal area in liver, OATP1B3 has been found to be expressed in several types of cancers. The expression of OATP1B3 in colon tumors and in the colon tumor cell lines was mainly cytoplasmic and clearly different from the membranous expression pattern in the normal liver. Cytoplasmic localization of OATP1B3 in tumor cells has also been found in primary breast cancer tissues. The aberrant expression of OATP1B3 in the cytoplasm of colon tumors was the impetus to investigate whether OATP1B3 functions differently in the setting of malignancy [8, 10] The SLCO1B3 gene sequence (encoding OATP1B3) was shown to vary among different populations as well as several SNPs were reported to date [16-21], therefore, the significance of SLCO1B3 polymorphisms on drug pharmacokinetics is becoming increasingly evident and the inter-ethnic differences exist in the allelic frequency of these variants suggests the need to characterize the full extent of SLCO1B3 genetic variability in any given population [17]. The study of polymorphisms of SLCO1B3 presents a special interest as they seem to be implicated in the function of the protein and promises a possible discrimination among patients in order to achieve personalized treatment. In addition, HRMA technique was chosen to serve as a powerful polymorphisms/mutation screening tool, based on the simplicity of the method, low cost, and high sensitivity and specificity. Moreover, the expression and cellular localization of OATP1B3 was assessed by immunohistochemistry, using the monoclonal mouse MDQ anti-OATP1B3 antibody, which recognizes the N-terminal region of OATP1B3, for the same tissue samples. High Resolution Melting (HRM) analysis is a polymerase chain reaction (PCR) based method for detecting DNA sequence variation by measuring changes in the melting point of a DNA duplex. Until recently, there are not data as far as it concerns the use of HRM as a gene scanning method for the gene of solute carrier organic anion transporter 1B3 (SLCO1B3) in FFPE tissues from patients with CRC. Moreover, there are limited data about its corresponding protein organic aniontransporting polypeptide 1B3 (OATP1B3). Materials and Method: We used 30 FFPE tumor tissue samples from patients diagnosed with CRC provided by the Department of Pathology of the General Hospital of Ioannina “G. Hatzikosta”. The institutional review board approved all of the protocols. Patient’s median age was 65 years; 13 were female and 17 male. Histologically, six cases were diagnosed as poorly, eighteen as moderate and six as well differentiated colon adenocarcinomas. The genomic alterations of SLCO1B3 exons were assessed by HRM while the expression and subcellular localization of OATP1B3 was carried out using immunohistochemistry. DNA extraction Up to 5 of 10μm FFPE tissue sections were gathered according to standard method [18] and were used for DNA extraction with “NucleoSpin® FFPE DNA” kit (Macherey-Nagel cat number 740980) according to manufacturers instructions. Extracted DNA was quantified using a NanoDrop 1000 Spectrophotometer (ThermoScientific). HRMA Analysis HRMA was performed on the LightCycler® 480 Real-Time PCR System, using the LightCycler® 480 High Resolution Melting Master Reaction Mix (Roche Diagnostics cat number 4909631001). Specific pairs of oligonucleotide primers (forward and reverse) were designed using Primer3 (version 3.0) to bracket each exon (Table 1) of SLCO1B3. The reference sequence gene of SLCO1B3 is formatted and downloaded from the Ensemble (http://www.ensembl.org/Homo_sapiens/Transcript/Exons?db=core;g=ENSG00000111700;r=12:20 963636-21243040;t=ENST00000261196). Equal quantity of DNA template of each sample was used in each a 20-μl reaction with 0.2 μM and 2.5mM final primer and MgCl2 concentration respectively. Cycling conditions were set as follows (Table 2): Pre-incubation/Denaturation of secondary structures 10 minutes at 950C, followed by 55 amplification cycles comprising of 1 min denaturation at 950C, followed by 60sec primer annealing T (according to each primer) and a 60sec elongation period at 720C. Final PCR product identification and genotype differentiation was carried on by a single cycle of High Resolution Melting Curve (950C for 60sec, 400C for 60sec, 650C for 1 sec). The Annealing temperature can be seen on table 1. Analysis of the experimental data with appropriate software Analysis of results was achieved by the LightCycler 480 Gene Scanning Software using the “Second Derivative Maximum/2nd Derivative” analysis method. The group with the most identical samples served as the “wild type” sequence for each exon. Thus any sample with a different melting peak than that of the wild type was considered to carry some form of genetic mutation. DNA Sequencing Sequencing analysis was performed on a representative sample of the “wild type” group and for each sample demonstrated genotypic differences. Sequence analysis Purified samples were sent for sequence to the VBC biotech Vienna. Results were assessed. The wild type of each exon was in accordance with the relatives from e!Ensembl (based on the site: Ensembl genome browser 67: Homo sapiens - Gene: SLCO1B3 ENSG00000111700. 2012). Then, each sequence was aligned with the corresponding wild type by using the multiple alignment algorithms in the Molecular Evolutionary Genetics Analysis 5.1 beta (MEGA 5.1beta). Moreover, each nucleotide sequence was translated, using MEGA 5.1beta. Immunohistochemistry Tissue sections of 3–4 µm width were cut, applied on microscope slides and incubated overnight at 650C for optimum tissue–glass adhesion. Deparaffinization, rehydration, and heat-induced epitoperetrieval (HIER) was achieved by incubating the slides in preheated (65 0C) pH 9 target retrieval solution (cat number S2375)for 20 minutes at 930C . DAKO’s Autostainer/PT link system was used for the immunostaining process. A 30-minute blocking step with 5% dry milk preceded the Ab application. Monoclonal antibody MDQ (mMDQ) (PROGEN Biotechnik, cat number 651140) was used for the immunolocalization of the N-terminal 24 amino acid epitope of OATP1B3, at a final concentration 1:10. Primary antibody was diluted with with Dako REAL™ Antibody Diluent (DAKO, Code S2022) in 1% blocking reagent and applied on slides for 30 minutes. Endogenous peroxidase was blocked using Daco REAL peroxidase blocking solution (Code S2023) for 10 minutes. DAKO’s special engineered Dextran backbone enriched with peroxidase molecules and goat secondary antibody molecules against rabbit and mouse immunoglobulins (Dako REAL™ EnVision™/HRP, Rabbit/Mouse ENV, Code Code K5007) was applied on slides for 20 minutes followed by a 5 minute Dako REAL™ DAB+ Chromogen (DAKO, Code K5007) detection system and a 2 minute hematoxylene (QS H-3404 Vector Laboratories) exposure. All incubation steps were performed at room temperature unless stated otherwise. Finally, sections were dehydrated with alcohol/xylene baths and stabilized with mounting medium. Immunostaining intensity was assessed by two experienced pathologists, who graded the results, using endothelial cells and tissue macrophages as internal controls. Results HRMA results with sequence confirmation Based on our results, we observed high polymorphism rate in the SLCO1B3 gene (table 3). Three previously reported polymorphisms, are identified, in exons 7, 12 and 14 which correspond to 699G>A with amino acid variation Met233Ile, encoding the OTP1B3/OATP-8-M233I (Rs7311358)[11, 19, 20], 1557 A>G with amino acid variation (Ala519Ala) encoding the OTP1B3/OATP-8-A519A (Rs2053098), and 1833G>A with amino acid variation Gly611Gly (Rs3764006), respectively. Moreover, in exon 5, one variant seems to correspond to an as yet unknown SLCO family member (Homo sapiens cDNA FLJ31312 fis, clone LIVER1000224, highly similar to Solute carrier organic anion transporter family member 1B3, dbj|AK055874.1|). Some other nucleotide substitutions which have not been reported yet, were found. Furthermore, the observed deletion and/or insertion of adenine was evaluated with caution as it might be caused by the use of formaldeyde during tissue fixation. Changes were also observed in the nucleotide sequence in the area of introns of exon 1 and 11. Immunohistochemistry The Immunohistochemical study revealed OATP1B3 was expressed in 27/30 studied cases and was located in the cytoplasm (Figure 2). Interestingly in positive cases, almost all cancer cells were stained positive. Furthermore, protein expression was intense in 40% of the cases studied while weak was the dominant pattern with 63,3% of studied cases. HRMA of the 3 OATP1B3 negative samples confirmed the presence of polymorphisms in exons 2 and 3 of the transcript SLCO1B3-001 which either led to early stop codons or other conformations of the tertiary protein structures prohibiting proper the antibody- epitope binding thus inability in protein detection. One of them had an insertion of 22 nucleotides in the area of exon 2 of the transcript SLCO1B3201, which causes deletion of the start codon. As a consequence, the protein OATP1B3 is not produced at all, making impossible for the mMDQ to detect. The other two cases have the same mutation, a deletion of Adenine and a substitution of Cytosine to Thymine in the second exon of the transcript SLCO1B3-00. This exon belongs to the untranslated area of the gene SLCO1B3. We suggest that these mutations may change the Ribosomal Binding Site (RBS), which is a sequence on mRNA that is bound by the ribosome when initiating protein translation. Discussion The great interest for SLCO1B3, as far as it concerns cancer, is that its protein OATP1B3, although it is expressed in the human liver under normal conditions, can be also expressed in various human cancer tissues that have been associated with prognosis and clinical outcomes. The expression of OATP1B3 in colon tumors and in the colon tumor cell lines was mainly cytoplasmic and clearly different from the membranous expression pattern in the normal liver. This is in accordance with our immunohistochemical results (Figure 2). The aberrant expression of OATP1B3 in the cytoplasm of colon tumors was the impetus to investigate whether OATP1B3 functions differently in the setting of malignancy [10]. The molecular entity of cancer-associated OATP1B, it remains undetermined. Only Nagai et al. (2012) [21] reported the identification of a new OATP1B3 mRNA isoform expressed in human colon and lung cancer tissues, which they named cancer-type OATP1B3 (Ct-OATP1B3).It was such data that raised our interest to investigate this transporter, applying HRMA in FFPE samples derived from patients with CRC. The upper goal was to scan possible polymorphisms/mutations of the transporter SLCO1B3 in this group of patient, with possible implications in the pathogenesis and treatment of CRC. In the present study, although the high levels of polymorphism which was observed in the exons of the SLCO1B3 gene, the results could not confirm that any of these polymorphisms presented with greater frequency in patients with CRC. Actually, they were identified three previously reported polymorphisms in exons 7, 12 and 14. In exon 5, one variant seems to correspond to an as yet unknown SLCO family member (Homo sapiens cDNA FLJ31312 fis, clone LIVER1000224, highly similar to Solute carrier organic anion transporter family member 1B3, dbj|AK055874.1|). In addition, many other novel variants were identified, which were not reported yet. As it is already known, in the general population, more than fifty SLCO1B3 polymorphisms, most of which are located in regulatory regions, have been identified along with a variety of haplotypes. Two clusters of deletions at -7 to -4 and -28 to -1 in the 5’-UTR that may result in reduced mRNA stability or problems with initiation of translation have been also reported [17, 20]. Among all these polymorphisms, functional analysis indicated that the variant 699G>A, which was also detected in our study, alters transport levels and kinetics of OATP1B3 and the change appears to be substratespecific, while 699G>A expression was not different from that of wild-type. Moreover, 699G>A is the most common OATP1B3 polymorphism in individual of all racial backgrounds (Hispanic Americans=0.833, Chinese American=0.795, Caucasian Americans=0.779, African Americans=0.478, Caucasian Europeans 0.71) [11, 19, 20]. This commonly inherited polymorphism M233I (as well as S112A) influences the degree to which testosterone is imported into cells through SLCO1B3 playing a possible important role in men with prostate cancer [22]. Immunohistochemically, it was revealed that three cases were completely negative for the mMDQ protein. A possible hypothesis is that these mutations may not permit the protein of OATP1B3 to be produced throughout. It was observed expression of the mMDQ antibody in the rest of the cases because the epitope of the antibody is found in the area of protein which is encoded by the second exon of the transcript SLCO1B3-201 or the third of the transcript SLCO1B3-001. Thus, mutations after this exon, deletions, insertions, or premature stop codons, might produce conformational changes in the OATP1B3 polypeptide, but they do not interfere with recognition of this epitope. However, nobody can exclude that others mutations also could exist in the positive immunohistochemical speciments. Neither the present study can elucidate the precise role of OATP1B3 in CRC. Because of the limited number of samples, only 30, the interpretation of the results was quite difficult. The use of more samples could possible show some polymorphisms/mutations to be presented more often in this group of patients. Our results could not confirm that a polymorphism or mutation was more often in the patients with CRC, suggesting a possible pathophysiological correlation with CRC. The three already reported variants that have been found may represent just polymorphisms of the population and they are not connected to the disease. It is noteworthy the fact that there are relatively often deletion and insertions of the base adenine. A possible explanation may be that the DNA was isolated from FFPE tissue. Analysis of nucleic acids from FFPE samples is crucial in today’s clinical research. It is known that the formalin fixation procedure lowers the success of polymerase chain reaction (PCR) amplification because of crosslinking between protein and DNA. In addition, standard embedding protocols require heating the formaldehyde-soaked samples. The temperatures used for embedding in paraffin cause further molecular reactions, some irreversible [23-28]. Artifacts could be the consequence of formalin damaging or cross-linking cytosine nucleotides, on either strand, so that the Taq DNA polymerase would not recognize them and instead of a guanosine incorporate an adenosine (because of the socalled A-rule). Thereby an artificial C-T or G-A mutation would be created. In the present study, some of the detected mutations regard A-G and C-T (Table 3). A great effort was made in order conditions of HRMA and concentrations of the reagents to be optimized. It has been proven that a careful optimization of HRMA is rewarded by high-throughput, economy, and simple and accurate performance of HRMA. Various techniques were employed to reduce non-specific amplification, such as increasing the annealing/extension temperature, reducing the primer concentration, optimizing the MgCl2 concentration. In the present study, the concentration of the salt (MgCl2) proved to be a very determinant factor of the method, as it may increase resolution and improve clustering [29]. Moreover, high concentration of DNA template was prohibitive in HRMA during the first applications of the method. When a few simple rules are taken into account (i.e., avoid long fragments and multiple melt domains), designing a HRMA screen for a gene is rather straightforward [28-31].HRMA Moreover, it seems to represent a more sensitive approach to detect a minimal fraction of mutated cells in neoplastic tissue that, in many cases, is not achievable by direct sequencing [32]. Among the many applications of HRMA method, HRMA provides a convenient way to detect SNP mutations in a targeted gene without performing full fragment sequencing. Although HRMA cannot define mutations by their melting transitions, it can significantly reduce the DNA sequencing burden, but positive results still require sequencing for diagnostic confirmation [27] Its ease of use, simplicity, flexibility, low cost, nondestructive nature, superb sensitivity, and specificity, make HRMA the method of choice to screen patients for pathogenic variants. Because HRMA is still a rather young technology, one can only expect exciting further developments. In spite of the problems of the quality of DNA in the present study, because it was derived from FFPE tissues and the several tests which were needed in order to standardise the method for each exon, HRMA remains a sensitive, scanning method that allows rapid detection of DNA sequence variations without cumbersome post–polymerase chain reaction (PCR) methods. The HRMA method gave us the possibility to screen most of the exons of SLCO1B3, sending for sequencing just a part of the samples. To our knowledge, this is the first study of SLCO1B3 gene using HRMA in FFPE tissue from patients with CRC and in comparison with immunohistochemistry. It was difficult the interpretation of the results because of the limited number of samples (30). Accurate determination of specificity requires analysis of large numbers of known wild-type samples. The “gold standard’ of the HRMA method could be achieved if PCR products for each exon were sequenced for polymorphisms variations and subsequently HRMA should be evaluated for every exon. This would help us to interpret better our experimental data of HRMA Archival tissue specimens, such as FFPE tissues, represent a vast source of tissue genomic DNA, easily obtained from clinical archives. Nowadays, the medicine lives the time of “targeted therapies” and needs to make use of all this archival tissue. In the fight against cancer, the request for rapid and reliable mutation screening in human cancers is continuously increasing for the definition of clinical samples and orienting targeted therapies. SLCO1B3 seems to be a quite good target as it seems to play role in the delivery of anticancer drugs. Its pathobiological significance in CRC may not have been yet elucidated, neither to our study. However, it seems to be an interesting molecule. The development of targeted therapies needs attractive techniques for mutation scanning with ease of use, high sensitivity and specificity, low cost and rapid sample turnaround. These requirements make HRMA ideal for use in routine clinical diagnostic settings. In addition, HRMA is an interesting method which combines biology (PCR amplification), physic (the phenomenon of fluorescence) and mathematic (the use of the software), three sciences in one.. Conclusions: The results of this study are of much interest as HRMA proved to be a reliable and rapid genotyping/scanning method for mutation detection of SLCO1B3. Moreover, it is important the finding that the immunohistochemical negative samples proved to have accommodate mutations which lead either to early stop codons or other conformations of the tertiary protein structures affecting the antibody- epitope binding. In the present study, HRMA shed light in SLCO1B3 gene, promising to reveal more in the near future. References 1. Ferlay, J., Steliarova-Foucher, E., Lortet-Tieulent, J., Rosso, S., Coebergh, J.W.W., Comber, H., Forman, D., Bray, F. Cancer incidence and mortality patterns in Europe: estimates for 40 countries in 2012. Eur J Cancer. 2013, 49(6):1374-403. 2. Siegel, R. L., Miller, K. D., Jemal, A. Cancer Statistics CA Cancer J Clin 2016, 66(1): 7-30. 3. Fakih, M. G. Metastatic colorectal cancer: current state and future directions. J Clin Oncol. 2015, 33 (6) 1809-1824. 4. 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The effects of CYP3A4, CYP3A5, ABCB1, ABCC2, ABCG2 and SLCO1B3 single nucleotide polymorphisms on the pharmacokinetics and pharmacodynamics of docetaxel in nasopharyngeal carcinoma patients. Cancer Chemother Pharmacol. 67(6): 1471-1478. 36. Galani V, Alexiou GA, Miliaras G, Dimitriadis E, Triantafyllou E, Galani A, Goussia A, Kanavaros P, Trangas T. Expression of Stem Cell Marker Nestin and MicroRNA-21 in Meningiomas. Turk Neurosurg. 2015;25(4):574-7. 37. Nakanishi, T. & Tamai, I. Genetic Polymorphisms of OATP Transporters and Their Impact on Intestinal Absorption and Hepatic Disposition of Drugs", Drug Metab Pharmacokinet. 2012, 27(1): 106-121. A. B1. SLCO1B3-201 B2. SLCO1B3-001 Figure 1: A. SLCO1B3 is located in chromosome 12 (2p12–31.7 to 12p12–37.2) (GeneCards. SLCO1B3. Genomic Location. 2012) B1. The map of the transcript SLCO1B3-201. B2. The map of the transcript SLCO1B3-001. Figure 2: Immunohistochemical staining of colon adenocarcinoma tissue Sample . There is cytoplasmic expression of the antibody in neoplastic and not in normal epithelial tissue. A: X40, B: X100 Table 1: Oligonucleotide primer sequences to carry out HRMA of the SLCO1B3 coding region Annealing Amplicon temperature Exon Forward primer Reverse Primer size (bp) (0C) 5'5'CATCATTGGACTCATAAAAA GAAATGTTTTAATTAGACAA 151 45 CAAA-3' CCTCGAC-3' 1 5'5'57 AACAGGTGATCATTTCAAA AATCCATTGCAGCGTCTTGT- 150 CCA-3' 3' 2 5'5'52 ATGTTCTTGGCAGCCCTGT- AAAGTTACCAATTTCAAAGC 150 3' TTCC-3' 3 5'5'TTCTAGGAAATTTGCTTGTG TGGCTCAGAGCTGTTTAACA ATTG-3' CTTA-3' 164 4 5'5'50 CAAAATGTTCAATTTCATGT TTTTTCTACTATCTCAGGTGA 152 TGC-3' TGTTCC-3' 5 5'5'57 AAAGTAAAACACTCTCTTG TCCAGGGAATGTAATCATGA TCTCGAT-3' AA-3' 219 6 5'5'48 ACAGGTAGTTTGAATGCAAT TGCACTTAAAAGACACTATC 150 AGGA-3' ATGG-3' 7 5'5'55 CGATTTTTGACTGGCTTCTT CAATTCCAAGTTGACAATGA TT-3' ATG-3' 315 8 5'5'55 TCCAGTCTTTGAAAAGCAT ACCCAACAAAAAGTTAGCAT 161 CC-3' GA-3' 9 5'5'55 AGAATGGGTGAATTTGGTT TGCACATAATCTTTTAATTTG 365 GA-3' ATGG-3' 10 5'5'55 CCCTCTCCTTATCCCCTTGT- GGAGAGGAGAAAAAGTGAA 3' AACT-3' 287 11 5'5'55 TTGGCAAATGTATTTGTTAA CATGACAATGTTTTACAGGAT 256 TATTTC-3' CA-3' 12 5'5'50 TGACATGTATTATTTCTTTGC AGTGTTCTTATAACCATTGAC CTTT-3' TGGAA-3' 100 13 5'5'50 TCTCATGTTGCAGGAGGAATTGTGTTTACGACAACTTACC 150 -3' CAAA-3' 14 5'363 15a 5'- 15b 16 TCGACTCTCTATTTTCTCTTT TCCATTGGTCCACTGTAAGTA TCACA-3' AA-3' 5'5'TCCAACATTCTTTACTTACA GGTTGGAAGAAGATCCATCG 459 GTGGA-3' -3' 5'5'GTGCATTTATCGCCACATTG- TTCATGCCTGAGGGAAACTT3' 3' 166 Table 2: The program of the Lightcycler® 480 Instrument. Detection Block Type Reaction Format Volume SYBR Green I 96 20 μl Programs Program name Cycles Analysis Mode Pre-Incubation 1 None Amplification 55 Quantification High Resolution 1 Melting Curve Melting Cooling 1 None Temperature Targets Target (0C) Acquisition Hold Ramp Acquisitions Mode (hh:mm:ss) Rate (0C/s) (per 0C) (96 wells) Pre- Incubation 95 None 00:10:00 4.4 Amplification 95 None 00:01:00 4.4 Primer None 00:01:00 2.2 dependent* 72 Single 00:01:00 4.4 High Resolution Melting 95 None 00:01:00 4.4 40 None 00:01:00 2.2 65 None 00:00:01 1/1 95 Continuous 25 Cooling 55 Table 3: Immunohistochemical expression of OATP1B3 (Score scale (0, 1+, 2+, 3+) reflecting antibody product expression intensity), and the type of mutation identified by HRMA in each case.