Yoon, Harry H.

Abstract Purpose: To determine the frequency and prognostic association of molecular markers by anatomic tumor site in patients with stage III colon carcinomas. Experimental Design: In a randomized trial of adjuvant FOLFOX ± cetuximab, BRAFV600E and KRAS (exon 2) mutations and DNA mismatch repair (MMR) proteins were analyzed in tumors (N = 3,018) in relationship to tumor location, including subsite. Cox models were used to assess clinical outcome, including overall survival (OS). Results: KRAS codon 12 mutations were most frequent at the splenic flexure and cecum; codon 13 mutations were evenly distributed. BRAF mutation frequency sharply increased from transverse colon to cecum in parallel with deficient (d) MMR. Nonmutated BRAF and KRAS tumors progressively decreased from sigmoid to transverse (all P < 0.0001). Significantly, poorer OS was found for mutant KRAS in distal [HR, 1.98; 95% confidence interval (CI), 1.49–2.63; P < 0.0001] versus proximal (1.25; 95% CI, 0.97–1.60; P = 0.079) cancers. BRAF status and outcome were not significantly associated with tumor site. Proximal versus distal dMMR tumors had significantly better outcome. An interaction test was significant for tumor site by KRAS (Padjusted = 0.043) and MMR (Padjusted = 0.010) for OS. Significant prognostic differences for biomarkers by tumor site were maintained in the FOLFOX arm. Tumor site was independently prognostic with a stepwise improvement from cecum to sigmoid (OS: Padjusted = 0.001). Conclusions: Mutation in BRAF or KRAS codon 12 was enriched in proximal cancers whereas nonmutated BRAF/KRAS was increased in distal tumors. Significant differences in outcome for KRAS mutations and dMMR were found by tumor site, indicating that their interpretation should occur in the context of tumor location. Clin Cancer Res; 21(23); 5294–304. ©2015 AACR.

Abstract Purpose: We examined the prognostic impact of specific KRAS mutations in patients with stage III colon adenocarcinoma receiving adjuvant FOLFOX alone or combined with cetuximab in a phase III trial (N0147). Analysis was restricted to BRAF–wild-type tumors, because BRAF mutation was associated with poor prognosis, and BRAF and KRAS mutations are mutually exclusive. Experimental Design: The seven most common KRAS mutations in codon 12 and codon 13 were examined in 2,478 BRAF–wild-type tumors. Because KRAS mutations in codon 12 (n = 779) or 13 (n = 220) were not predictive of adjuvant cetuximab benefit, study arms were pooled for analysis. Disease-free survival (DFS) was evaluated by HRs using Cox models. Results: KRAS mutations in codon 12 (multivariate HR, 1.52; 95% confidence interval, CI, 1.28–1.80; P < 0.0001) or codon 13 (multivariate HR, 1.36; 95% CI, 1.04–1.77; P = 0.0248) were significantly associated with shorter DFS compared with patients with wild-type KRAS/BRAF tumors, independent of covariates. KRAS codon 12 mutations were independently associated with proficient mismatch repair (P < 0.0001), proximal tumor site (P < 0.0001), low grade, age, and sex, whereas codon 13 mutations were associated with proximal site (P < 0.0001). Conclusion: KRAS mutations in either codon 12 or 13 are associated with inferior survival in patients with resected stage III colon cancer. These data highlight the importance of accurate molecular characterization and the significant role of KRAS mutations in both codons in the progression of this malignancy in the adjuvant setting. Clin Cancer Res; 20(11); 3033–43. ©2014 AACR.

BACKGROUNDHuman epidermal growth factor receptor 2 (HER2) is a therapeutic target in patients with esophageal adenocarcinoma (EAC), with gene amplification used as a selection criterion for treatment, although to the authors' knowledge the concordance between amplification and HER2 protein expression remains undefined in EAC. Furthermore, the association between HER2 and its interacting partner, human epidermal growth factor receptor 3 (HER3), is unknown yet appears to be of potential therapeutic relevance.METHODSPatients with untreated EACs (N = 673) were analyzed for HER2 amplification and polysomy 17 by fluorescence in situ hybridization in parallel with immunohistochemistry (IHC) (IHC scores of 0‐1+, 2+, and 3+). Amplification was defined as HER2/CEP17 ≥ 2. HER3 expression by IHC was analyzed in randomly selected cases (n = 224). IHC and fluorescence in situ hybridization results were compared using least squares linear regression.RESULTSOverall, 17% of the EACs (116 of 673 EACs) were HER2‐amplified with an amplification frequency that was highest among IHC3+ cases (89%) and declined among IHC2+ cases (13%) and IHC0 to IHC1+ cases (4%). Among HER2‐amplified cases, the level of amplification increased linearly with HER2 membranous expression (HER2/CEP17 ratio: 7.9 in IHC3+ and 5.5 in IHC2+ vs 2.8 in IHC0 to IHC1+ [P < .0001]), with 14% of amplified tumors demonstrating absent/faint expression (IHC0 to IHC1+). Polysomy 17 was not found to be associated with HER2 expression. Cytoplasmic HER3 expression was detected in 87% of tumors (195 of 224 tumors) and was found to be significantly associated with better differentiation (P < .0001). Stepwise increases in HER3 expression were associated with higher HER2 expression levels (P = .0019).CONCLUSIONSLevels of HER2 protein expression and amplification were found to be linearly associated and highly concordant. Among amplified tumors with absent/faint expression, the level of amplification was low. Frequent expression of HER3 suggests its relevance as a therapeutic target, and its significant association with HER2 supports ongoing efforts to inhibit HER2/HER3 in patients with EAC. Cancer 2014;120:415–424. © 2013 American Cancer Society.

Purpose There is increasing recognition of the existence of intratumoral heterogeneity of the human epidermal growth factor receptor (HER2), which affects interpretation of HER2 positivity in clinical practice and may have implications for patient prognosis and treatment. We determined the frequency and prognostic impact of heterogeneous HER2 gene amplification and polysomy 17 in patients with esophageal adenocarcinoma (EAC). Patients and Methods HER2 amplification (by fluorescence in situ hybridization) was examined in surgical EAC specimens (n = 675). HER2 heterogeneity was defined according to consensus guidelines as gene amplification (HER2/CEP17 ratio ≥ 2.0) in more than 5% but less than 50% of cancer cells. No patient received neoadjuvant or HER2-targeted therapy. Cox models were used to assess disease-specific survival (DSS) and overall survival (OS). Results Overall, 117 EACs (17%) demonstrated HER2 amplification, of which 20 (17%) showed HER2 heterogeneity. All HER2-heterogeneous tumors were amplified. Among HER2-amplified tumors, heterogeneous tumors had significantly higher frequency of poor histologic grade and polysomy 17. In multivariable models that included number of metastatic lymph nodes, grade, tumor stage, and polysomy 17, only HER2 heterogeneity and node number were prognostic among HER2-amplified tumors, with heterogeneity showing worse DSS (hazard ratio, 2.04; 95% CI, 1.09 to 3.79; P = .025) and OS (P = .026). Among HER2-nonamplified EACs, polysomy 17 was independently associated with worse DSS (P = .012) and OS (P = .023). Conclusion Among HER2-amplified EACs, 17% show HER2 heterogeneity, which independently predicts for worse cancer-specific death. Among HER2-nonamplified EACs, polysomy 17 is independently associated with worse survival. These novel findings demonstrate aggressive subgroups in HER2-amplified and -nonamplified EACs that have important implications for HER2 analysis and determination of benefit from HER2-targeted therapy.

Abstract Background: Esophageal adenocarcinoma (EAC) is a lethal cancer, and the incidence is increasing. Our group demonstrated that over-expression of the epidermal growth factor receptor (EGFR) correlated with reduced survival in EAC. Panitumumab (P) is a fully human IgG2 monoclonal antibody against human EGFR. Cetuximab combined with irinotecan (I) has shown activity for second-line treatment of advanced colorectal cancer (CRC). P alone is active in EGFR expressing CRC as well. Our group has empiric evidence for the activity of cetuximab + I as third-line treatment for advanced EAC. As such, a phase II study was designed to evaluate P + I as second-line therapy for advanced EAC. Trial Design: The primary endpoint is overall response (OR) as measured by RECIST (cross-sectional imaging every 2 cycles). Secondary endpoints include overall survival, safety/toxicity and correlative studies. Patients with confirmed EAC with history of one prior treatment are treated with P 9 mg/m2 on day 1 and I 125 mg/m2 on days 1 and 8 of each 21 day cycle to a maximum of 6 cycles. Inclusion criteria include confirmed EAC, measurable disease, no prior I or P, PS &lt;2 and normal organ function. A Simon two-stage design is used with power of 80% and a type I error of 0.05. 18 patients will be tested in the first stage and will terminate the trial if 2 or fewer respond. A total of 43 patients will be studied. Blood and tissue are obtained to analyse the role of FCα-R receptors as well EGFR pathway components and kras mutations. Enrollment: The 1st patient was enrolled in May 2009. Through August 2011, 7 patients received treatment. Preliminary results: Of the 7 patients treated, all are white males, median age 62. 2 patients completed 6 cycles. 1 patient received 3 cycles, 3 received 2 cycles and 1 patient completed 1 cycle. 3 patients are still alive. However, only 1 patient is still in the trial. 4 patients received dose reductions due to grade 3 or 4 side effects, including GI disturbances (5), fatigue(1), skin rash(1), electrolyte imbalances(2) and hematologic abnormalities (5). Reasons for discontinuation included progressive disease (PD, 5 patients) and patient refusal (2). The longest survival was 338 days–1 of the 2 patients who completed 6 cycles. The second patient who completed 6 cycles is alive at 307 days. 1 patient completed 3 cycles and survived 213 days after PD. 1 patient survived 174 days followed PD after 2 cycles. 2 patients completed 2 cycles and are still alive, surviving 151 (pt refusal) and 103 days respectively. The shortest survival was 85 days who completed only 1 cycle. Conclusion: Preliminary data from this Phase II trial suggests that patients with advanced EAC might benefit from P+I regimen as 2nd line therapy. 3 additional centers will open the trial. Accrual is ongoing, and correlative studies will follow. This project used the University of Pittsburgh Cancer Institute and was supported in part by award P30CA047904 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3708. doi:1538-7445.AM2012-3708

Abstract Purpose: We examined the frequency, tumor characteristics, and prognostic impact of HER2 protein expression and gene amplification in patients with curatively resected esophageal adenocarcinoma (EAC). Experimental Design: HER2 expression was analyzed by immunohistochemistry (IHC) in surgical EAC specimens (n = 713). Gene amplification was examined by FISH in a large subset (n = 344). Most tumors were T3–4 (66%) or node positive (72%); 95% were located in the esophagus or gastroesophageal junction. No patient received neoadjuvant therapy. Cox models were used. Results: Overall, 17% of EACs were HER2 positive (i.e., IHC3+ or IHC2+ with amplification), with strong agreement between HER2 amplification (HER2/CEP17 ratio ≥2) and expression (κ = 0.83). HER2 positivity was significantly associated with lower tumor grade, less invasiveness, fewer malignant nodes, and the presence of adjacent Barrett's esophagus (BE). EACs with BE had higher odds of HER2 positivity than EACs without BE, independent of pathologic features [OR = 1.8 (95% CI: 1.1–2.8), P = 0.014]. Among all cases, HER2 positivity was significantly associated with disease-specific survival (DSS) in a manner that differed by the presence or absence of BE (Pinteraction = 0.0047). In EACs with BE, HER2 positivity was significantly associated with improved DSS [HR = 0.54 (95% CI: 0.35–0.84), P = 0.0065] and overall survival (P = 0.0022) independent of pathologic features, but was not prognostic among EACs without BE. Conclusions: HER2 positivity was shown in 17% of resected EACs and associated with reduced tumor aggressiveness. EACs with BE had nearly twice the odds of being HER2 positive and, within this subgroup, HER2 positivity was independently associated with improved survival. Clin Cancer Res; 18(2); 546–54. ©2012 AACR.

PurposeAlthough the importance of obesity in colon cancer risk and outcome is recognized, the association of body mass index (BMI) with DNA mismatch repair (MMR) status is unknown.Patients and MethodsBMI (kg/m2) was determined in patients with TNM stage II or III colon carcinomas (n = 2,693) who participated in randomized trials of adjuvant chemotherapy. The association of BMI with MMR status and survival was analyzed by logistic regression and Cox models, respectively.ResultsOverall, 427 (16%) tumors showed deficient MMR (dMMR), and 630 patients (23%) were obese (BMI ≥ 30 kg/m2). Obesity was significantly associated with younger age (P = .021), distal tumor site (P = .012), and a lower rate of dMMR tumors (10% v 17%; P < .001) compared with normal weight. Obesity remained associated with lower rates of dMMR (odds ratio, 0.57; 95% CI, 0.41 to 0.79; P < .001) after adjusting for tumor site, stage, sex, and age. Among obese patients, rates of dMMR were lower in men compared with women (8% v 13%; P = .041). Obesity was associated with higher recurrence rates (P = .0034) and independently predicted worse disease-free survival (DFS; hazard ratio [HR], 1.37; 95% CI, 1.14 to 1.64; P = .0010) and overall survival (OS), whereas dMMR predicted better DFS (HR, 0.59; 95% CI, 0.47 to 0.74; P < .001) and OS. The favorable prognosis of dMMR was maintained in obese patients.ConclusionColon cancers from obese patients are less likely to show dMMR, suggesting obesity-related differences in the pathogenesis of colon cancer. Although obesity was independently associated with adverse outcome, the favorable prognostic impact of dMMR was maintained among obese patients.

Purpose Given that smoking affects body mass index (BMI) and survival, stratification by smoking status may be required to determine the true prognostic impact of BMI. Although obesity increases risk for developing esophageal adenocarcinoma (EAC), the prognostic influence of obesity and its potential modification by smoking status is unknown in this disease. Patients and Methods All patients (N = 778) underwent potentially curative esophagectomy. BMI was calculated using measured height and weight at surgery and categorized as obese (≥ 30 kg/m 2 ), overweight (25 to 29.9 kg/m 2 ), or normal (18.5 to 24.9 kg/m 2 ). Cigarette smoking was categorized as never or ever. The association of BMI with disease-specific survival (DSS), disease-free survival (DFS), and overall survival (OS) was determined by Cox regression. Results Excess BMI was significantly associated with DSS in a manner that differed substantially by smoking status (P for interaction = .023). Among never smokers, obesity was significantly associated with adverse DSS (hazard ratio [HR] = 2.11; 95% CI, 1.31 to 3.43; P = .002), DFS (HR = 2.03; 95% CI, 1.30 to 3.18; P = .002), and OS (HR = 1.97; 95% CI, 1.24 to 3.14; P = .004), as compared with normal weight, after adjusting for covariates. By contrast, among ever smokers, obesity was not prognostic, and overweight status was significantly associated with favorable survival in univariate, but not multivariate, analysis. Conclusion Obesity among never smokers was independently associated with two-fold worsening of DSS, DFS, and OS after surgery for EAC, after adjusting for known prognostic factors. These data, in one of the largest reported resected EAC cohorts, are the first to show an adverse prognostic impact of obesity in EAC.