Immunohistochemical and oncogenetic analyses of the esophageal basaloid squamous cell carcinoma in comparison with conventional squamous cell carcinomas

Basaloid squamous cell carcinoma of the esophagus is a rare variant of squamous cell carcinoma. We reviewed 878 cases of esophageal squamous cell carcinoma and detected 22 cases (3%) of basaloid squamous cell carcinoma. These tumors and stage-matched paired conventional squamous cell carcinomas were investigated for clinicopathologic features and immunoreactivity of cytokeratin subtypes, p53, B-cell lymphoma 2 (bcl-2), beta-catenin, and epidermal growth factor receptor. Molecular aberrations in p53, CTNNB1 (the gene encoding beta-catenin), and epidermal growth factor receptor (EGFR) were also determined. Patients with basaloid squamous cell carcinomas demonstrated a 5-year survival rate of 42%, significantly worse than those with well-differentiated squamous cell carcinoma (P < .01). Histologically, solid nests with central necrosis and a cribriform pattern were identified in almost all (>= 95%) cases, and ductal differentiation was less frequent (45%) but associated with significantly better survival (P < .05). Compared with conventional squamous cell carcinomas, the basaloid squamous cell carcinomas were less immunoreactive for cytokeratin 14, cytokeratin 903, and membranous beta-catenin (P < .01-.001) but more reactive for bcl-2, nuclear beta-catenin, epidermal growth factor receptor, and Ki-67 (P < .05-.001). Direct sequencing showed mutations of p53 (36%), EGFR (14%), but not CTNNB1; fluorescent in situ hybridization detected amplification of the epidermal growth Actor receptor gene (22%). In basaloid squamous cell carcinomas, low-level expression of cytokeratin 14/cytokeratin 903 and mutations of p53 and EGFR had a significant influence on worse survival (P < .05-.001). We conclude that the esophageal basaloid squamous cell carcinoma, a neoplasm with particularly aggressive biologic behavior, should be differentiated from conventional squamous cell carcinomas. In this context, immunohistochemical assessment of several markers might provide a useful adjunct diagnostic tool. Aberrations of p53 and epidermal growth factor receptor genes are possibly involved in progression of esophageal basaloid squamous cell carcinoma. (C) 2012 Elsevier Inc. All rights reserved.