Cancer of the oesophagus ranks as the ninth most common malignancy in the world, and recent evidence shows that its incidence is increasing. Prognosis of this disease is poor, with an overall 5-year survival rate of less than 10%. Bcl-2 proto-oncogene is a known inhibitor of apoptosis with special importance in the development, progression and prognosis of various human cancers. Therefore the expression of bcl-2 protein has been evaluated in the multistage oesophageal tumorgenesis, which progress from normal mucosa to dysplasia to in situ to invasive oesophageal squamous carcinoma.

Aims: Studying the expression pattern of bcl-2 in esophageal squamous cell carcinoma and to correlate it with known prognostic parameter (cellular differentiation and depth of invasion). Methods and results:  This retrospecive study included 5 cases of normal esophageal mucosa, 4 cases dysplastic epithelium, 6 cases in situ carcinoma and 28 cases of resected esophageal carcinoma. All specimens were formaline-fixed, paraffin-embedded tissues. Immunostaining for bcl-2 protein was done using avidin-biotin peroxidase method. Cases scored as positive if immunostaining was detected in more than 25% of tumor cells. In normal mucosa, bcl-2 immunoreactivity was restricted to the basal-cell layer. Bcl-2 was expressed in three/four (75%) cases of dysplastic epithelium, 6/6 (100%) cases of in situ carcinoma and 18/28 (64.3%) cases of oesophageal invasive carcinoma.  As regard to the differentiation, 8/8 (100%) cases of well differentiated tumor, 8/13 (61.5%) cases of moderately differentiated tumor and 2/7 (28.6%) cases of poorly differentiated tumor showed bcl-2 expression (p. = 0.0001). Considering the depth of invasion; 5/6 (83.3%) cases of T1, 7/9(77.8%) cases of T2, 5/9 (55.6%) cases of T3, and ¼ (25%) cases of T4 showed bcl-2 expression (p. = 0.0001).

Conclusions: High bcl-2 expression, especially in pre-invasive lesions, plays a role in oesophageal carcinogenesis and regarded as a marker for disease progression. In invasive oesophageal carcinoma, its correlation with known prognostic parameter (cellular differentiation and depth of invasion) proves its prognostic value.