Basaloid squamous carcinoma of the esophagus with analysis by in situ nickend labeling and PCNA immunostaining

BACKGROUND/AIMS: Basaloid squamous carcinoma (BSC) of the esophagus has bee n associated with poor outcome after surgery. In this study, apoptosis and cell proliferation of BSC were studied to evaluate the malignant potential of this cancer. METHODOLOGY: In tissue samples from 4 out of 5 BSC patients (1 patient with pre-operative radiotherapy was excluded) and from 30 patients with squamou s cell carcinomas (SCCs) of the esophagus, apoptosis was studied by termina l deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin ni ck end labeling (TUNEL), and cell proliferation was evaluated by the immuno staining of proliferating cell nuclear antigen (PCNA). Two of the 5 patient s with BSC died of recurrence and the remaining 2 patients are alive withou t recurrence. RESULTS: TUNEL-positive cells and PCNA-positive cells were observed to exis t randomly and independently in the BSC samples. In the well- and moderatel y differentiated SCCs, TUNEL-positive cells and PCNA-positive cells were lo cally observed. The apoptotic index was significantly lower in the BSC than in the SCC tissues, and the PCNA labeling index was significantly higher i n BSC than in SCC. CONCLUSIONS: These results suggest that BSC of the esophagus has great prol iferative activity and weak apoptosis. These characteristics may reflect th e aggressive behavior and poor prognosis of esophageal BSC. Early detection of this tumor, as in the present 2 cases, will contribute to a better prog nosis.