Expression of a plant-associated human cancer antigen in normal, premalignant and malignant esophageal tissues

To study the relationship between the expression profiles of a plant-associated human cancer antigen and carcinogenesis of esophagus and its significance.

We analyzed expression of a plant-associated human cancer antigen in biopsy specimens of normal (n=29), mildly hyperplastic (n=29), mildly (n=30), moderately (n=27) and severely dysplastic (n=29) and malignant esophageal (n=30) tissues by immunohistochemistry.

The plant-associated human cancer antigen was mainly confined to the cytoplasm and showed diffuse type of staining. Positive staining was absent or weak in normal (0/30) and mildly hyperplastic tissue samples (2/29), while strong staining was observed in severe dysplasia (23/29) and carcinoma in situ (24/30). There was significant difference of its expression between normal mucosa and severely dysplastic tissues (P<0.001) or carcinoma in situ (P<0.001). Significant difference was also observed between mild dysplasia and severe dysplasia (P<0.001) or carcinoma in situ (P<0.001). An overall trend toward increased staining intensity with increasing grade of dysplasia was found. There was a linear correlation between grade of lesions and staining intensity (r=0.794, P<0.001). Samples from esophageal cancer showed no higher levels of expression than those in severely dysplastic lesions (P>0.05).

The abnormal expression of this plant-associated human cancer antigen in esophageal lesions is a frequent and early finding in the normal-dysplasia-carcinoma sequence in esophageal carcinogenesis. It might contribute to the carcinogenesis of esophageal cancer. The abnormal expression of this plant-associated human cancer antigen in esophageal lesion tissues may serve as a potential new biomarker for early identification of esophageal cancer.