Oliver A. Press

Molecular Determinants of Cetuximab Efficacy

PURPOSEnTo investigate whether mRNA expression levels of cyclin D1 (CCND1), cyclooxygenase 2 (Cox-2), epidermal growth factor receptor (EGFR), interleukin 8 (IL-8), and vascular endothelial growth factor (VEGF), all members of the EGFR signaling pathway, are associated with clinical outcome in patients with EGFR-expressing metastatic colorectal cancer (CRC) treated with cetuximab.nnnPATIENTS AND METHODSnThirty-nine patients with metastatic CRC, refractory to both irinotecan and oxaliplatin, were enrolled on IMCL-0144 and treated with single-agent cetuximab. The intratumoral mRNA levels of CCND1, Cox-2, EGFR, IL-8, and VEGF were assessed from paraffin-embedded tissue samples using laser-capture microdissection and quantitative real-time polymerase chain reaction.nnnRESULTSnThere were 21 women and 18 men with a median age of 64 years (range, 35 to 83 years). Higher gene expression levels of VEGF were associated with resistance to cetuximab (P = .038; Kruskal-Wallis test). The combination of low gene expression levels of Cox-2, EGFR, and IL-8 was significantly associated with overall survival (13.5 v 2.3 months; P = .028; log-rank test). Both findings were independent of skin toxicity that was itself significantly correlated to survival. Patients with a lower mRNA amount of EGFR had a longer overall survival compared with patients that had a higher mRNA amount (7.3 v 2.2 months; P = .09; log-rank test). Patients with lower expression of Cox-2 had a significantly higher rate of grade 2 to 3 skin reactions under cetuximab treatment.nnnCONCLUSIONnThis pilot study suggests that gene expression levels of Cox-2, EGFR, IL-8, and VEGF in patients with metastatic CRC may be useful markers of clinical outcome in single-agent cetuximab treatment.

Association of Methylenetetrahydrofolate Reductase Gene Polymorphisms and Sex-Specific Survival in Patients With Metastatic Colon Cancer

PURPOSEnMethylenetetrahydrofolate reductase (MTHFR) is a key enzyme regulating intracellular folate levels, which affects DNA synthesis and methylation. Two MTHFR gene polymorphisms, C677T and A1298C, are linked to altered enzyme activity. Several studies have shown these two polymorphisms to be associated with response to fluorouracil (FU) -based treatment in advanced colon cancer patients, but data are inconsistent and contradictory. Meanwhile, epidemiologic studies demonstrated that these MTHFR polymorphisms were associated with cancer risk in a sex-specific manner. We tested the hypothesis of whether these two polymorphisms are associated with sex-specific clinical outcome in metastatic colon cancer patients treated with FU-based chemotherapy.nnnPATIENTS AND METHODSnThis study included 318 patients (177 men and 141 women) with metastatic colon cancer treated between 1992 and 2003 at the University of Southern California/Norris Comprehensive Cancer Center or Los Angeles County/University of Southern California Medical Center. Peripheral blood samples were collected from each patient, and genomic DNA was extracted from WBCs. Two MTHFR gene polymorphisms (C677T and A1298C) were tested by fluorogenic 5-nuclease assay.nnnRESULTSnThe A1298C polymorphism showed statistically significant differences in overall survival (OS) in female, but not male, patients with metastatic colon cancer (log-rank test, P = .038). Among females, OS was greater for patients with the A/A genotype (n = 67; median OS, 18.4 months) compared with patients with the A/C genotype (n = 50; median OS, 13.9 months) or C/C genotype (n = 10; median OS, 15.6 months).nnnCONCLUSIONnAlthough preliminary, these data support the role of the A1298C polymorphism in MTHFR as prognostic marker in female patients with metastatic colon cancer. Further studies are needed to confirm these findings.

Genomic profiling associated with recurrence in patients with rectal cancer treated with chemoradiation

PURPOSEnStage II and III adenocarcinoma of the rectum has an overall 5-year survival rate of approximately 50%, and tumor recurrence remains a major problem despite an improvement in local control through chemotherapy and radiation. The efficacy of chemoradiation therapy may be significantly compromised as a result of interindividual variations in clinical response and host toxicity. Therefore, it is imperative to identify those patients who will benefit from chemoradiation therapy and those who will develop recurrent disease. In this study, we tested whether a specific pattern of 21 polymorphisms in 18 genes involved in the critical pathways of cancer progression (i.e., drug metabolism, tumor microenvironment, cell cycle regulation, and DNA repair) will predict the risk of tumor recurrence in rectal cancer patients treated with chemoradiation.nnnPATIENTS AND METHODSnA total of 90 patients with Stage II or III rectal cancer treated with chemoradiation were genotyped using polymerase chain reaction (PCR)-based techniques for 21 polymorphisms.nnnRESULTSnA polymorphism in interleukin (IL)-8 was individually associated with risk of recurrence. Classification and regression tree analysis of all polymorphisms and clinical variables developed a risk tree including the following variables: node status, IL-8, intracellular adhesion molecule-1, transforming growth factor-beta, and fibroblast growth factor receptor 4.nnnCONCLUSIONnGenomic profiling may help to identify patients who are at high risk for developing tumor recurrence, and those who are more likely to benefit from chemoradiation therapy. A larger prospective study is needed to validate these preliminary data using germline polymorphisms on tumor recurrences in rectal cancer patients treated with chemoradiation.

Gender-Related Survival Differences Associated with EGFR Polymorphisms in Metastatic Colon Cancer

Evidence is accumulating supporting gender-related differences in the development of colonic carcinomas. Sex steroid hormone receptors are expressed in the colon and interact with epidermal growth factor receptor (EGFR), a gene widely expressed in colonic tissue. Increased EGFR expression is linked with poor prognosis in colon cancer. Within the EGFR gene there are two functional polymorphisms of interest: a polymorphism located at codon 497 (HER-1 R497K) and a dinucleotide (CA)(n) repeat polymorphism located within intron 1. These germ-line polymorphisms of EGFR were analyzed in genomic DNA from 318 metastatic colon cancer patients, 177 males and 141 females, collected from 1992 to 2003. Gender-related survival differences were associated with the HER-1 R497K polymorphism (P(interaction) = 0.003). Females with the HER-1 497 Arg/Arg variant had better overall survival (OS) when compared with the Lys/Lys and/or Lys/Arg variants. In males the opposite was true. The EGFR dinucleotide (CA)(n) repeat also trended with a gender-related OS difference (P(interaction) = 0.11). Females with both short <20 (CA)(n) repeat alleles had better OS than those with any long >or=20 (CA)(n) repeats. In males the opposite was true. Combination analysis of the two polymorphisms taken together also revealed the same gender-related survival difference (P(interaction) = 0.002). These associations were observed using multivariable analysis. The two polymorphisms were not in linkage disequilibrium and are independent of one another. This study supports the role of functional EGFR polymorphisms as independent prognostic markers in metastatic colon cancer. As a prognostic factor, these variants had opposite prognostic implications based on gender.

ABCB1, SLCO1B1 and UGT1A1 Gene Polymorphisms Are Associated with Toxicity Line Irinotecan

We tested specific gene polymorphisms known to be involved in the irinotecan (CPT-11) metabolic pathway. The combination of at least one SLCO1B1 521 T allele, one ABCB1 1236 C allele and one UGT1A1*28 variant 7 repeat demonstrated a statistically significant association with Grade 3/4 toxicities in metastatic colorectal cancer patients.

Gender-related survival differences associated with polymorphic variants of estrogen receptor-β (ERβ) in patients with metastatic colon cancer.

Estrogen replacement therapy in women has shown a protective effect on the development of colonic carcinomas. Gender-related differences in the development of colonic carcinomas have also been reported. Estrogen receptor-β (ERβ) is expressed in colon carcinomas and has shown prognostic value in colon cancer patients. This study investigated an ERβ 3′ non-coding polymorphism associated with transcriptional activity to determine clinical outcome in patients with metastatic colon cancer. Genomic DNA from 318 metastatic colon cancer patients, 177 males and 141 females, were collected from 1992 to 2003. These patients were analyzed for CA repeat polymorphism of the ERβ gene. Gender-related survival differences were associated with an ERβ (CA)n repeat polymorphism (P for interaction=0.003, the likelihood ratio test). Female patients with any short <22 (CA)n repeat alleles had shorter overall survival (OS) compared with female patients who had both long ⩾22 (CA)n repeat alleles. In the male patients, the opposite OS difference was found. This study supports the role of an ERβ (CA)n repeat polymorphism as a prognostic marker in metastatic colon cancer; however, this prognostic factor had opposite implications based on gender.

Association of Cyclin D1 (CCND1) gene A870G polymorphism and clinical outcome of EGFR-positive metastatic colorectal cancer patients treated with epidermal growth factor receptor (EGFR) inhibitor cetuximab (C225)

3518 Background Cetuximab (C225) is a chimeric anti-EGFR monoclonal antibody with efficacy against EGFR-positive metastatic colorectal cancer. Recently, the link between EGFR signaling and the cell cycle has been identified. In vitro studies show blockade of EGFR by C225 can induce cell cycle arrest in the G1 phase which mediated by inhibition of interactions between cyclins and CDKs and increases expression of the cell cycle inhibitor p27KIP1. A frequent A870G polymorphism in the final codon of exon 4 of the Cyclin D1, leads gene alternatively spliced to produce two different mRNA transcripts [a] and [b] was also identified. In vivo studies have indicated this polymorphism can affect the prognosis of patients with different types of solid tumors. We hypothesized that CCND1 A870G polymorphism will predict clinical outcome in EGFR-positive metastatic colorectal cancer patients treated with EGFR inhibitor Cetuximab(C225). Methods Cyclin D1 A870G gene polymorphism was tested using PCR-RFLP method in genomic DNA extracted from peripheral blood from 39 metastatic colorectal cancer patients enrolled in a phase II EGFR inhibitor Cetuximab(C225) clinical trial. ResultsWe found a significant association between A870G polymorphism and overall survival of patients treated with Cetuximab(C225). With median follow-up 8.7 months (range 2.5, 11.7) and median survival time 4.8 months (95%C.I 2.7, 8.5), Patients with AA homozygous genotype survived a median time of 2.3 months (95%C.I 2.1, 5.7) compared with those have homozygous GG genotype 4.4 months (95%C.I 1.8, 9.8+) or heterozygous AG genotype 8.5 months(95%C.I 5.5, 11.7+), respectively (p<0.05, logrank test). ConclusionsThese data suggest that Cyclin D1 A870G polymorphism may be a potential prognostic molecular marker for clinical outcome of the EGFR-positive metastatic colorectal caner patients treated with third line EGFR inhibitor Cetuximab (C225). Prospective studies are needed to confirm these preliminary findings. [Table: see text].

Characterization of HER2 status by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC).

The use of human epidermal growth factor receptor type 2 (HER2) gene amplification and overexpression as a molecular predictive marker has become critically important for proper selection of breast cancer patients for treatment with targeted therapeutic agents such as trastuzumab, lapatinib, pertuzumab, and T-DM1. A high level of sensitivity and specificity of molecular tests for this alteration is desirable. The American Society of Clinical Oncology and College of American Pathology have jointly established consensus guidelines to standardize characterization of this alteration in breast cancers. This chapter provides a brief overview of pre-analytic and analytical processing of breast specimens as well as subsequent molecular evaluation for HER2 status.

Polymorphisms in IL-8 and the GSTP1 are associated with survival of metastatic colorectal cancer patients treated with CPT-11

3606 Background Irinotecan (CPT-11), an analogue of Camptothecins, demonstrates a broad spectrum of antitumor activity. Currently, there are no prognostic molecular markers for CPT-11 efficacy. Therefore, we investigated associations between polymorphisms in genes involved in CPT-11 metabolism (UGT1A1), chemoresistance (GSTP1), DNA repair (XPD, ERCC1, XRCC1, Werner 1074, and Werner 1367), and angiogenesis (IL-8 and COX-2) and survival of patients with metastatic colorectal cancer receiving CPT-11 based chemotherapy. In vivo studies show GSTP1 to detoxify chemotherapeutic agents by glutathione conjugation. In vivo and in vitro studies show IL-8 to possess angiogenic properties and its overexpression is associated with metastasis potential in colorectal cancer. Positional cloning studies identified Werner as the gene responsible for Werner Syndrome (WS), and cells from these patients have been shown to be particularly sensitive to Camptothecin. Methods The gene polymorphisms were tested using PCR-RFLP method on genomic DNA extracted from peripheral blood from metastatic colorectal cancer patients treated with CPT-11. Results 55 patients were collected; 31 males and 24 females; median age 55 (range 34-77) years. The response to CPT-11 was 40% (18/45, 1 pt was inevaluable, and 9 pts are still receiving treatment and were too early to be evaluated), with median survival of 22.9 (95% CI: 18.4, 29.3) months. The median time of follow-up and range was 15.4 (4.7-26.1) months. Individually, IL-8 and GSTP1 showed trends for overall survival (log rank p=0.07 and p=0.077, respectively). A combined analysis of these two genes showed patients carrying two favorable genotypes (homozygous Ile for GSTP1 and T allele for IL-8) had longer survival when compared with those patients carrying no favorable genotypes or only 1 favorable genotype (p=0.005). The Werner Loci polymorphisms also showed a trend for overall survival. Conclusion These data suggest that IL-8, GSTP1, and the Werner Loci polymorphisms may be potential prognostic molecular markers for clinical outcome of metastatic colorectal cancer patients treated with a CPT-11 regimen. [Table: see text].

Gene expression profiling associated with risk of recurrence in patients with colorectal cancer

3602 Background: Early identification of patients at increased risk for recurrence remains a central issue in the treatment of colorectal cancer. Altered expression levels in cancer-related genes h...