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Cancer Chemoprevention & Surrogate End Point Markers JianYu Rao, M.D. Associate Prof. Of Pathology UCLA CANCER PREVENTION • PRIMARY • STOP THE EXPOSURE • SECONDARY • INTERVENTION OR CHEMOPREVENTION • TERTIARY • TREATMENT CHEMOPREVENTION • Administrating specific amounts of a particular natural or synthetic chemical in an attempt to identify agents that will prevent, halt or reverse the process of carcinogenesis • The basic assumption is that treating early stages of malignant process will halt the progression of malignancy • The key is to define early lesions, and treat the malignant field Exposure to Carcinogen Birth Precancerous Intraepithelial Lesions, (PIN, CIN, PaIN..) Additional Molecular Event CHEMOPREVENTION Cancer Multiyear progression from initiation and early precancerous lesions to invasive disease in major cancer target organs Kelloff et al. 2000 (Fig. 1) THEORIES SUPPORT FOR CHEMOPREVENTION • EPIDEMIOLOGICAL EVIDENCE: • OVER 50% CANCERS HAVE NO KNOWN RISK FACTORS • NUMEROUS EVIDENCE TO DEMONSTRATE THE INVERSE RELATIONSHIPS OF SOME NUTRIENT FACTORS WITH CANCER RISKS THEORIES SUPPORT FOR CHEMOPREVENTION (Cont.) • EXPERIMENTAL EVIDENCE: • ALTHOUGH CARCINOGENESIS IS REGARDED AS NONREVERSIBLE PROCESS, STUDIES SHOWED THIS IS ONLY TRUE AT LATE STAGE. IN FACT, A LARGE PORTION OF THE LONG LATENCY PERIOD OF CARCINOGENIC PROCESS IS REVERSIBLE. • IN VITRO CULTURE AND IN VIVO ANIMAL STUDIES IDENTIFIED NUMEROUS AGENTS THAT CAN REVERSE, OR HALT THE CARCINOGENESIS PROCESS, PARTICULARLY AT THE EARLY STAGE. THEORIES SUPPORT FOR CHEMOPREVENTION (Cont.) • CLINICALLY • ADVANCES IN CERTAIN TYPES OF CANCER TREATMENT HAVE LIMITED SUCCESS IN REDUCING THE OVERALL INCIDENCE, OR EVEN MORTALITY OF CANCER. Chemoprevention: Some Terminologies • INDIVIDUAL RISK AND STRATIFICATION • INTERMEDIATE END POINT MARKER (SURROGATE END POINT MARKER) • FIELD CANCERIZATION • MULTI-PATH OF CARCINOGENESIS RISK STRATIFICATION • Identification of AT-RISK subjects who are also SUSCEPTIBLE to treatment: LEGEND: Not at risk to develop disease At risk of developing disease, biology A, responsive to agent X At risk of developing disease, biology B, NOT responsive to agent X INTERMEDIATE END POINT MARKER (SURROGATE END POINT MARKER) • These are prevention biomarkers which are specifically related to early stages of carcinogenesis. • These markers are used to identify individual’s risk for developing cancer and to monitor the effectiveness of intervention methods. FIELD CANCERIZATION • The whole field of tissue of a particular organ is exposed to the carcinogenic insult and is at increased risk for developing cancer. • Although only a few foci eventually develop malignancy, the other areas are not necessary entirely “normal”. • Most common epithelia cancers are developed through this mechanism. Examples of such cancers are: Head and neck ca, bladder ca, breast ca, lung ca, GI ca, etc. MULTI-PATH OF CARCINOGENESIS • The current model of carcinogenesis is that cancer develops through multiple events which are not necessary through linear steps, but rather through overlapping networks. TARGET POPULATION INDIVIDUALS AT RISK = LATENCY (20 YEARS) x # EXPECTED TO DIE IN ONE YEAR (1.1 MILLION) = 22 MILLION CHEMOPREVENTION IN DIFFERENT RISK CATEGORIES Risk category Parameter General Population High Risk Agent toxicity Trivial to none Slight Selection method Public Health Clinical Other consideration Use dietary supplements may be applicable Need biomarkers From lee W. Wattenberg, P.S.E.B.M., 1997 216:133-141. Phase I Trial Objectives: • To determine the intervention’s short-term (<1 yr.) dose-toxicity relationship • To determine the intervention’s human pharmacokinetics Design: • • • • Single arm, nonrandomized Multiple dose levels Less than 1 yr. duration Accrual 25-100 Phase II Trial Objectives: • To determine the intervention’s side effects • To determine optimal recruitment methods of the target population • To determine retention of study participants to the study intervention and procedures • To determine optimal methods for the conducting of a phase III trial • To determine the effect of the intervention on biomarkers of carcinogenesis (phase II b) Design: • • • • Randomized, double-blind, placebo-controlled Multiple dose levels or agents One to five years in duration Accrual 100s-1000s Phase III Trial Objectives: • To determine the effect of the intervention on the cancer incidence (total and specific cancer type) • To determine the effect of the intervention on death rate and disease incidence • To determine the long-term side effects of the intervention • To determine the nature history of specific biomarkers of carcinogenesis (placebo group) and the effect of the intervention agent (treatment group) on these markers. Design: • • • • Randomized, double-blind, placebo-controlled Multiple dose levels or agents, alone or in combination Five to ten years in duration Accrual 1000s-10,000s UNIQUE FEATURES OF CHEMOPREVENTION • Participants are usually healthy or at least “cancer free” • The degree and incidence of side effects that are acceptable are low • The end point is disease prevention, not disease response • The incidence of the study end point is low CATEGORIES OF CHEMOPREVENTIVE AGENTS • BLOCKING CARCINOGEN METABOLISM AND EXPOSURE • INCREASE TISSUE RESISTANCE/DIFFERENTIAITON • TARGETING ONCOGENIC PATHWAYS CATEGORIES OF CHEMOPREVENTIVE AGENTS • BLOCKING AGENTS • Prevent metabolic activation of carcinogens or tumor promoters • Enhance detoxification Glutathione-S-transferase,Oltipraz • Trap reactive carcinogenic species: Glutathione, N-Acetylcysteine • Vaccines: HBV, HPV CATEGORIES OF CHEMOPREVENTIVE AGENTS (Cont.) • INCREASING TISSUE RESISTANCE • Induce tissue maturation/differentiaiton Pregnancy or hormonal induced maturation of terminal ducts of breast - decrease breast cancer Retinoids, DMFO, etc • Decrease target tissue function Castration - reduce risk of prostate ca • Decrease cell proliferation Low fat diet decrease epithelial proliferation rate in intestinal tract - reduce colon cancer risk CATEGORIES OF CHEMOPREVENTIVE AGENTS (Cont.) • PATHWAY SPECIFIC AGENTS • Cox-2 inhibitors • Anti-angiogenesis • Anti-EGFR • Hormone antagonists • Augmenting tumor suppressor functions • Inhibiting oncogenic activities (e.g., Ras) CHEMOPREVENTION TO HUMANS UPDATE • BREAST CANCER • Two agents showed promising results: Tamoxifen and retinoids • Animal model well established • PROSTATE CANCER • SCID model established • Hormonal modulation may have potential • PCPT Trial – Finasteride (5-a-reductase, 5mg/day) • 2-arm trial, 18,882 subjects, 7 yrs • PCP=18.4% vs 24.8% in treated vs ctrl group • Ongoing Trial: Selenium/Vit E trial CHEMOPREVENTION TO HUMANS UPDATE (CONT.) • GASTRIC AND ESOPHAGEAL CANCER • A combination of beta carotene, vitamin E, and selenium may be effective in early stage lesions, but not late severe dysplastic lesions. • LUNG CANCER • Beta-carotene or alpha-tocopherol showed reverse effect in lung cancer risk in heavy smokers in Finland • Ongoing trials with COX-2 inhibitor in former smokers here at UCLA CHEMOPREVENTION TO HUMANS UPDATE (CONT.) • COLON CANCER • Sulindac, a nonsteroidal anti-inflammatory compound hold great promise. Others, such as Oltiparz, selenium, and antioxidants vit. E/A, etc, may also be effective. • HEAD AND NECK CANCER • Retinoids showed promising results in both animal models and human studies. PROBLEMS OF CHEMOPREVENTION • TOO LONG • TOO LARGE COHORT • TOO MUCH COST ANSWER: NEED TO DEVELOP RELIABLE SEMS BIOMARKERS OF CANCER • CLINICAL SETTINGS (TUMOR MARKERS) • EPIDEMIOLOGICAL AND PREVENTIVE SETTINGS (INTERMEDIATE END POINT OR SURROGATE END POINT MARKERS). CURRENT CLINICALLY USED TUMOR MARKERS • PSA - Prostate Adenocarcinoma • Alpha FP - Hepatoma & some Ovarian Ca • HCG - Choriocarcinoma • CEA - Ovarian CA BIOMARKERS • Genetic susceptibility markers • Markers of exposure • Markers of biological effects -Detect early lesions -Prognostic indicators GENETIC SUSCEPTIBILITY MARKERS • Glutathione S-transferase (GST) M1 and T1 • N-acetyl transferase (NAT) • Cytochrome P-450 • DNA repair gene defect (Lynch syndrome) MARKERS OF EXPOSURE • Metabolic product of carcinogen in urine • DNA, RNA and hemoglobin adducts -Reflects only current exposure -Only a small fraction of DNA adducts will result in mutation • DNA repair targets BIOMARKERS OF EFFECT • Reflect the interactions of genetics and exposures and so the first choice for SEM • If they persist, may also be the markers of disease • Histopathologic evaluation is the “gold standard” HOW TUMOR MARKERS ARE USED CLINICALLY • Early detection • Predict the biological potential of cancer (metastasize and recurrence) • Monitor the effectiveness of therapy Exposure to Carcinogen Birth Precancerous Intraepithelial Lesions, (PIN, CIN, PaIN..) Additional Molecular Event Cancer Surrogate End Point Markers Genetic Suscep. Marker Markers for Exposure Markers of Effect CHEMOPREVENTION Tumor Markers CRITERIA FOR SELECTING SEM • FITS EXPECTED BIOLOGICAL MECHANISM • BIOMARKER AND ASSAY PROVIDE ACCEPTABLE SENSITIVITY, SPECIFICITY, AND ACCURACY • BIOMARKER IS EASILY MEASURED • BIOMARKER MODULATION CORRELATES TO DECREASED CANCER INCIDENCE FITS EXPECTED BIOLOGICAL MECHANISM • DIFFERENTIALLY EXPRESSED IN NORMAL AND HIGH RISK TISSUE • CLOSELY LINKED, EITHER DIRECTLY OR INDIRECTLY, TO CAUSAL PATHWAY FOR CANCER • MODULATED BY CHEMOPREVENTIVE AGENTS • LATENCY IS SHORT COMPARED WITH CANCER ASSAY VALIDITY • ASSAY SHOULD BE STANDARDIZED AND VALIDATED • DOSE-RELATED RESPONSE TO THE CHEMOPREVENTIVE AGENT IS OBSERVED • STATISTICALLY SIGNIFICANT DIFFERENCE BETWEEN LEVELS IN TREATMENT GROUPS AND CONTROLS OTHER ASSAY ISSUES • BIOMARKER CAN BE OBTAINED BY NONINVASIVE TECHNIQUES • ASSAY IS NOT TECHNICALLY DIFFICULT • MULTIPLE MARKERS CAN BE EVALUATED SIMULTANEOUSLY IN LIMITED SAMPLE VOLUMES • COST • FALSE POSITIVE OR FALSE NEGATIVE RESULTS ARE LESS IMPORTANT, IN COMPARING WITH CLINICAL TUMOR MARKERS CATEGORIES OF SEM • HISTOLOGICAL AND MORPHOMETRIC MARKERS • PROLIFERATION, DIFFERENTIATION AND INVASION MARKERS • SPECIFIC ONCOGENES/GROWTH REGULATORS • MARKERS OF GENETIC AND EPIGENETIC INSTABILITY POTENTIAL SEMS FOR BREAST, COLON AND PROSTATE Breast Histological DCIS, LCIS, ADH Proliferation Differentiation Genetic Biochemical Colon Prostate Adenomatous polyps Aberrant polyps PIN S-phase fraction Ki-67 S-phase fraction Brdu Uptake, PCNA PCNA Ki-67 Myoepithelial (s-100 Vimentin), etc BGA, Mucin core ag Cytokeratins HM Cytok BGA, actin Onc (erb-2, myc fos, ras) Suppressor (p53) Estradiol Onc (ras, myc, src) Suppressor (p53, DCC) Onc (erb-2) Ornithine Decarboxylase Polyamine TGF-beta, PSA SEM Modulation in Chemoprevention • Complete Phenotypic Response -idea • Less Than Complete Phenotypic Response -Genotypic markers to distinguish chemoprevention from selecting regressing of existing disease – true effect is seen if post-treated lesion has less genotypic change than baseline or control) • No Response. Genome Wide Genotypic SEM Analysis • Identify high risk population • Identify individuals with genetic susceptibility for treatment (pharmacogenomics) • Monitoring/analyzing individual’s treatment response Issues in Using SEM • The observed SEM change may not correlate with end point (cancer incidence). • Can not measure the quality of life. • Adverse effect may not be observed in short term SEM studies. Lessons learned from SELDI-TOF • Initial study on patient serum from cancer patients (ovarian, prostate, etc) versus cancer showed very promising results (nearly 100% sensitivity/specificity to separate cancer from normal) – Used case-control design – Only 2 group-comparison (cancer vs. normal) – No validation • However, recent validation studies were rather disappointing Biomarker-Directed Targeted Design • Increase the efficiency of the trial, but depends on: – The performance of the biomarker test (sensitivity/specificity) – Size of the treatment effect for targetnegative patients BIOMARKER STUDY DSEIGN a. Untargeted Design: Treatment Register Randomize Control b. Untargeted Design: Treatment Register Test Biomarker Biomarker Randomize + Control BIOMARKER STUDY DSEIGN Biomarker by Treatment Interaction Design: Treatment Biomarker Randomize + Control Register Test Stratify Biomarker Treatment Biomarker Randomize Control BIOMARKER STUDY DSEIGN Biomarker Based Strategy Design: Biomarker + Treatment A Test Biomarker Biomarker - Treatment B Register Randomize No Biomarker Evaluation Treatment B BIOMARKER STUDY DSEIGN Modified Biomarker Based Strategy Design: Biomarker + Treatment A Test Biomarker Biomarker - Treatment B Register Randomize Treatment A No Biomarker Randomize Evaluation Treatment B Actin Remodeling As a Target for Biomarker Development NORMAL CA Morphological hallmarks of cancer cells: •Altered N/C-ratio •Altered membrane (cytoplasmic and nuclear) •Loss of cell adhesion •Increased motility/invasion/met. •etc.. ALMOST All ARE RELATED TO ACTIN REMODELING WHAT TO DO WITH THIS? HYPOTHESIS/RATIONALE • Altered cytoskeletal proteins, e.g., actin remodeling, is the foundation for malignant morphological phenotype • Thus, signaling pathways associated actin remodeling may provide a potential target for anti-cancer drug development as well as biomarkers for a more objective assessment of malignant transformation and progression • These targets can be identified through genomic/proteomic approach Model in Focal Adhesions F-Actin Tenuin VASP Zyxin - Ras Sup. Family (Rac/Rho/CDC42) Vinculin Tensin ECM Actinin - pp60sro - pp125FAK -Abl Paxillin p-Tyr? Talin b a Substrate R/E/M Integrin b a PM ACTIN ASSCOIATED MOLECULARS IMPLICATED IN MALIGNANT TRANSFORMATION • Oncogene signal transduction pathways – Ras family ( GTPase): • Rho (stress fibers) • Rac (lamellipodia) • Cdc42 (filopodia) – Src family (tyrosine kinase)* – FAK* * Relate to intergin signaling • Tumor Suppresor – Gelsolin* – Tropomyosin/merlin – Alpha-actinin* – E-cadhelin – Beta-Catanin – Vinculin – Fodrin* *Implicated in apoptosis Increased cellular F-actin is a marker of cellular differentiation Using leukemic cell lines: HL-60- Transformed/Differentiable Daudi- Transformed/Undifferentiable RPMI - Nontransfomed We demonstrated that increased Factin content is associated with cellular differentiation (J. Rao, Cancer Res., 1990) In contrast, loss of F-actin is a marker for cellular transformation and bladder cancer risk Bladder wash samples from a spectrum of cases with various risk for TCC show a strong correlation of loss of cellular F-actin contents with increased bladder cancer risk. (J. Rao, Cancer Res., 1991) Furthermore, actin alteration is a field disease marker for bladder cancer A careful mapping analysis on touch prep slides obtained from distant, adjacent and tumor tissues showed that increased G-actin is seen in over 50% of the distant field epithelial cells of cancer bearing bladder. (J. Rao, P.N.A.S., 1993) QFIABiomarker Profile G-actin: Texas-Red conjugated DNase I M344: FITC (or Rhodamin) 3Step Immunofluorescence DNA: Hoechst or DAPI Test Our Our Biomarker Biomarker Profile Profile )Test to to Detect Detect Bladder Bladder Cancer Cancer in in Workers Workers Exposed Exposed to to Cancer Cancer Causing Causing Chemicals Chemicals Study Design in Worker Risk Assessment Study 1788 Workers Very High Risk High Risk Positive Cystoscopy TREAT Negative Moderate Risk 373 controls Monitor in 1 yr Monitor in 3 yrs Low Risk Screen Workers Markers Exposure Physical Exam Questionnaire Smoking Asses. Classify Risk Action/Intervention Procedures in Screening Program ! Notification of of exposed exposed workers. workers. !Notification ! Selection of of matching matching controls. controls. !Selection ! Administration of of questionnaire. questionnaire. !Administration 66Occupational Occupational history. history. 66Medical Medical history. history. 66Genitourinary Genitourinary tract tract history. history. 66Smoking Smoking assessment. assessment. ! Physical examination. examination. !Physical ! Urinalysis !Urinalysis ! Papanicolaou cytology cytology !Papanicolaou ! DNA, M344, M344, G-actin G-actin biomarkers biomarkers !DNA, Pathology Summary 6 30 Cancers detected ) 29 Transitional Cell Carcinoma ) 1 Squamous Cell Carcinoma 6 4 Cases of Muscle Invasion (>T2) 6 20 Cases Grades 1-2; 8 Cases Grade 3. Incidence Rate (per 100,000 person-year) of Bladder Cancer in the Cohort Exposed to Benzidine ( 1991-1997) Cohort No. of Subjects Followed Age ( Mean ± SD ) Cancer Cases Incidence Unexposed 373 57.7 ± 10.8 2 87.23 Exposed 1788 55.4 ± 10.5 28 263.35 Total 2161 55.8 ± 10.5 30 232.11 TEST POSITIVE PRIOR TO OR AT THE TIME OF DIAGNOSIS NO. OF RATE BIOMARKERS POSITIVE/NO. POSITIVE % OF CASES QFIA HIGH OR MODERATE RISK PAP CYTOLOGY HEMATURIA 28/29 96.5 15/28 53.6 4/28 14.3 Biomarker Results of Cohort Study Detection Sensitivity Specificity OR PPV DNA 67 87 12.8 5.2 M344 55 98 55 23.1 High Risk 68 91 21.1 8.3 HM or P 86 70 15 3.4 PAP 62 99 244 48.1 Biomarker Results of Cohort Study Risk Assessment Sensitivity Specificity OR PPV DNA 88 87 46 2.7 M344 50 98 46 9.1 High Risk 63 91 17.3 2.9 HM or P 88 70 16.6 1.3 PAP 14 99 24.7 6.7 Cox Proportional Regression Model with Time Dependent Covariates Biomarkers DNA G-actin M344 PAP Hematuria High or Middle Risk High Risk Risk Ratio1 16.2 3.2 37.9 14.7 5.1 13.5 25.5 95% Confidence Limits 7.1 - 37.0 1.2 - 8.4 16.8 - 85.3 6.2 - 34.6 1.2 - 22.1 5.3 - 34.7 11.0 - 59.1 1. Risk ratios were adjusted by age and total months of exposure Lead Time to Tumor Detection During the Follow-up (1991-1997) Total Cases=25* N % Cases Mean Months Moderate Risk 10** 40 33 High Risk 23 92 15 Pap 16 64 8 Hematuria 4 16 3 ** 44cases caseswere were excluded excluded due due to to their theirdetection detection at atthe the initial initial screen. screen. 11 case case was wasexcluded excluded due due to to the the error error of of sample sample collection. collection. **** 88out of 10 cases progressed to high risk prior to out of 10 cases progressed to high risk prior to tumor tumor detection. detection. Abnormal G-actin in the Field Predicts Tumor Recurrence Cellular actin levels can be used to monitor the effectiveness of chemoprevention •Cellular F/G-actin levels in the non-tumor field epithelial cells after tumor was removed by TUR predicted the recurrence potential of the tumor. •In addition, cellular F/G-actin levels fluctuate from abnormal to normal as results of chemopreventive effect of differentiation agent DMSO. (G.P. Hemstreet, J. Rao, Cancer Det. And Prev., 1999) SUMMARY: Actin Remodeling in Cancer • Actin remodeling as a generalized marker for: – Cancer field changes – Precancerous lesions – and thus, a candidate for chemopreventive SEM • However: – Measuring actin remodeling is technically challenging • New method/tools are needed Nanomechanical analysis of cancer cell softness/elasticity • Atomic Force Microscope: – A new tool for cancer research – Ideal for analyzing the functional role of actin remodeling in various cellular events in single living cells – Combine functional analysis with morphology at nanometer level NEWS HEADLINES • Nanotechnology shows cancer cells are 'softer' than normal cells • Microscopic 'tools' can identify cancer cells by 'feel‘ • Nano breakthrough in cancer detection: study • …. (a) (b) (b) Force (a) (c) Displacement Fig. 1. Schematic of an AFM tip (a) approaching, (b) indenting and (c) retracting from a cell (c) 0 hr 6 hr 24 hr Average Young’s Modulus (E) values for A549 human lung adenocarcinoma cells treated with or without (ctrl) 40 ug/mL green tea extract (GTE) for 6 and 12 hours, respectively. Ctrl GTE Effects of GTE on the migration of A549 cells. Confluent monolayers of cells were maintained in a serum free media and a lane was scraped through the monolayers of the cells with a plastic micropipette tip. The cells were allowed to migrate across the lane at 37 oC for 6 or 24 h in the presence (40 µg/ml) or absence of GTE. The distance that cells migrated into the area of the wound at different points was photographed using a computer imaging system. Top panels: GTE untreated; lower panels: GTE treated (40 μg/ml). A B Mesothelial cells Tumor Phase-contrast D C Adhesion Force Measured between Mesothelial Cells and Cancer Cells 8 Mesothelial cells Cancer cells 7 Measurement 6 Counts 5 4 3 2 1 300 250 200 150 100 50 0 E AF 0 0 50 100 150 200 250 Young's Modulus (E) 300 350 400 AFM Measurements c a (ii) (i) b d “Chemoprevention of Superficial Bladder Cancer in Former Smokers” Parallel, Randomized, Double-blind, Placebo-Controlled, Phase II Adjuvent Studies of Erlotinib and Polyphenol E to Prevent the Recurrence and Progression of Tobacco-Related, High-grade Superficial Bladder Cancer U01-CA-96116 Study Objectives • Primary: – To evaluate the effects of a daily dose of PE, Erlotinib, and placebo on tumor recurrence for pts with superficial bladder ca (former smokers) • Secondary: – To assess toxicities of PE and Erlotinib – To correlate the modulation of biomarkers with tumor recurrence/progression – To assess the effects of PE and Erlotinib on tumor progression Study Design • Phase II, randomized, double-blinded, placebo-controlled, 3-arm trials • A random permuted study design with one stratification factor (Ta vs T1 vs CIS) • Two agents: PE- 800mg/daily, Erlotinib (up to 100mg/daily • 330 former smokers (<12 months) with prior superficial bladder ca Placebo Stage Ta T1 CIS Treatment PE Erlotinib Specimen Types • Blood • Urine cytological specimens – Voided urine – Catheterized urine – Bladder wash • Tissue – Biopsy – Cystectomy specimen Key Secondary Biomarkers • Cytology • QFIA Profile: – DNA & G-actin by LSC – M344/19A211/LDQ10 by Immunocyt kit • Microsatellite Instability Markers (M.S.I.) • bFGF • Survivin Biomarker Core Urinary Cytology Tissue Blood 5 cc (VU/CU/BW, 100 cc each) (ca, random) (20 cc) Store 10 cc 2-bFGF Thin Prep (3) 1 slide 2- Cytology Leukocyte Brook’s lab Fresh Frozen 2 slide 2-QFIA Rao’s Lab Store (Rao’s lab) Paraffin Emb. Plasma 3- Genetic Polym. (Zhang’s lab) 1- Histology 4- Polyphenol (Heber’s lab) 3- Tissue Array Extract Genomic DNA 2- M.S.I. (Core facility) EGFR, Ki67, Gelsolin, p53, etc (Seligson’s lab) 3- Genetic Polymorphism (Zhang’s lab) 1- Primary end point 2- Secondary end point 3-Tertiary end point 4- Compliance marker Summary • Biomarker is needed in Chemoprevention Trial to: – Detect early preventable lesions – Monitoring the efficacy • Actin remodeling and associated cellular nanomechanical changes provide a wealth of targets for chemopreventive biomarker selection: – Actin change occurs in premalignant field lesion – Chemopreventive agents (e.g., green tea) modulates actin remodeling – Actin change can be detected either by traditional biochemical assays or AFM measurements of cellular nanomechanics