Discordant HER2 expression and response to neoadjuvant chemoradiotherapy in esophagogastric adenocarcinoma.

BACKGROUND: Targeting human epidermal growth factor receptor 2 (HER2) with trastuzumab in metastatic esophagogastric adenocarcinoma (EGA) improves survival. The impact of HER2 inhibition in combination with chemoradiotherapy (CRT) in early stage EGA is under investigation. This study analyzed the pattern of HER2 overexpression in matched-pair tumor samples of patients who underwent neoadjuvant CRT followed by surgery. METHODS: All patients with EGA who underwent standard neoadjuvant CRT followed by esophagectomy at the University of Florida were included. Demographics, risk factors, tumor features, and outcome data were analyzed. Descriptive statistics, Chi-square exact test, uni- and multivariate analyses, and Kaplan Meier method were used. HER2 expression determined by immunohistochemical (IHC) was scored as negative (0, 1+), indeterminate (2+) or positive (3+). RESULTS: Among 49 sequential patients (41 M/8 F) with matched-pair tumor samples, 9/49 patients (18%) had pathologic complete response (pCR), 10/49 had near pCR or not enough tumor (NET) to examine in the post- treatment samples. Patients with initial HER2 negativity demonstrated conversion to HER2 positivity after neoadjuvant CRT (7/30 cases; 23%). Baseline HER2 overexpression was more common in lower stage/node negative patients (67% in stages I, IIA vs. 33% in stages IIB, III) and did not correlate with treatment response or survival. CONCLUSIONS: Although limited by a relatively small sample size, our study failed to demonstrate that baseline HER2 protein over-expression in EGA predicts response to standard CRT. However, our data suggested that HER2 was up regulated by CRT resulting in unreliable concordance between pre-treatment (pre-tx) and post-treatment (post-tx) samples. Pre-therapy HER2 expression may not reliably reflect the HER2 status of persistent or recurrent disease.

EGFR family and cMet expression profiles and prognostic significance in esophagogastric adenocarcinoma.

BACKGROUND: Targeted therapy with anti-human epidermal growth factor receptor-2 (HER2) monoclonal antibody in patients with HER2 overexpressed esophagogastric adenocarcinoma (EGA) improves survival; however, the effect is transient due to the development of resistance. Some studies suggest that cMet overexpression provides cross talk for epidermal growth factor receptor (EGFR) and HER2 inhibition. We sought to characterize the expression profile of the EGFR family and cMet receptors in untreated, resected EGA. METHODS: This retrospective analysis included all sequential patients with esophageal or gastroesophageal junction (GEJ) adenocarcinoma who underwent primary resection, without neoadjuvant therapy or HER2 inhibition, with adequate tissue, at the University of Florida from 2001 to 2011. Central blinded immunohistochemistry (IHC) was performed on tumor specimens with EGFR, HER2, HER3, HER4 and cMet expression scored as low (0, 1+) or high (2+, 3+). Demographic and tumor characteristics were compared using Fisher exact test. Kaplan-Meier curves and univariate analysis compared survival among different receptors. RESULTS: Total 52 patients were included in the study with median age 66 years. High expression of EGFR (73%), HER2 (40%), HER3 (75%), HER4 (35%) and cMet (69%) was detected among the study group. HER3 and HER4 co-expression was found in 18 (35%) cases. Pan expression of all four EGFR family members with cMet was noted in only 17% of cases. On univariate analysis, tumor stage and depth correlated with survival, while cMet + HER3 +/- EGFR receptor co-expression trended towards a worse survival. CONCLUSIONS: EGFR family and cMet are frequently co-expressed in treatment naïve resected EGA or GEJ tumors. Although our data do not significantly show receptor status as a prognostic factor, the co-expression profiles support for further investigation to improve targeting of this signal transduction axis.

Clinical, morphologic, and immunophenotypic characteristics of ampullary carcinomas with an emphasis on SMAD4 expression.

BACKGROUND: The purpose of our study was to examine the relationship between clinicopathologic variables and morphologic subtypes in ampullary carcinoma, with an emphasis on the expression of SMAD4 tumor suppressor gene. METHODS: Sixty-three cases of ampullary carcinomas resected between 2000-2011 were included in this study. Clinical characteristics and outcome data were recorded. Tumors were classified as pancreatobiliary or intestinal type based on morphology, and immunohistochemical (IHC) studies for cytokeratin 7 (CK7), cytokeratin 20 (CK20), cytokeratin 17 (CK17), and SMAD4 were performed. RESULTS: Forty-nine percent of the ampullary tumors were pancreatobiliary, 29% were intestinal, and 22% were other variants. Tumors with pancreatobiliary morphology showed worse overall survival than those with intestinal morphology or other variants (P=0.03). A trend for higher stage, recurrence and less survival was seen in cases with negative SMAD4 expression. In multivariate analysis, age group (≤60 vs. >60 years) and expression of CK17 were the most prognostic of survival. CONCLUSIONS: Ampullary tumors with pancreatobiliary morphology have a worse overall survival, while negative SMAD4 expression is associated with a trend of less survival.

Interobserver variability of mitotic index and utility of PHH3 for risk stratification in gastrointestinal stromal tumors.

OBJECTIVES: Accurate grading of gastrointestinal stromal tumors (GISTs), based on mitotic index, can be problematic. METHODS: In this study, we compared interobserver variability in detecting mitosis on H&E with PHH3 immunohistochemistry (IHC). In addition, we examined the correlation between H&E mitosis and Ki-67 and the association of PHH3 and Ki-67 with overall survival. Four pathologists independently reviewed 50 GIST cases. RESULTS: Intraclass correlation coefficients showed good interobserver variability for mitotic counts on both H&E (0.918; 95% confidence interval [CI], 0.874-0.950) and PHH3 IHC (0.923; 95% CI, 0.882-0.953). Nineteen (38%) cases were graded higher and five (10%) cases were downgraded by at least one observer using PHH3 compared with H&E. Using receiver operating characteristic curve analysis, a PHH3 cutoff of seven or more mitoses was associated with worse overall survival (P = .028). Ki-67 showed poor correlation with H&E mitotic counts and overall survival (P = .077). CONCLUSIONS: PHH3 may thus be a valuable adjunct for risk stratification in GISTs.

Distinguishing Ménétrier's disease from its mimics.

OBJECTIVE: Ménétrier's disease (MD) is a rare hypertrophic gastropathy characterised by giant rugal folds, hypochlorhydria, protein loss and a classic constellation of symptoms (nausea, vomiting, abdominal pain and peripheral oedema). It is considered a clinical diagnosis that may at times be difficult to establish. Firm diagnostic criteria for MD are proposed by delineating the clinicopathological features that best differentiate MD from its mimics. METHOD: 48 patients referred to Vanderbilt University Medical Center for consideration of enrolment in a clinical trial of treatment of patients with MD with cetuximab were evaluated for a definitive diagnosis by assessing the clinical presentation, pertinent laboratory values and histopathological features. RESULTS: MD was confirmed in 25 of the 48 patients (52%). The remaining 23 patients were considered to be mimics of MD, the most common diagnoses being gastric polyps or polyposis syndromes (13/23, 57%). Gastric slides were available from 40 of the 48 patients for detailed histological analysis (22/25 MD and 18/23 non-MD). Foveolar hyperplasia, glandular tortuosity and dilation, and a marked reduction in parietal cell number were present in all 22 cases of MD. Lamina propria smooth muscle hyperplasia and oedema characterised most cases (18/22 and 19/22, respectively). More than half had prominent eosinophils (11/22) and/or plasma cells (12/22) in the lamina propria. The clinical presentation of patients with MD was characterised by significantly younger age of onset, male predominance and increased vomiting compared with non-MD patients, and a lower prevalence of anaemia compared with MD patients with polyps. There was a trend towards increased frequency of peripheral oedema in patients with MD compared with non-MD patients. CONCLUSIONS: MD is most accurately diagnosed by clinicohistopathological analysis including oesophagogastroduodenoscopy with gastric pH, appropriate laboratory tests (complete blood count, serum albumin, serum gastrin, Helicobacter pylori and cytomegalovirus serology) and full-thickness mucosal biopsy of the involved gastric mucosa.