Differential reduction in the expression of keratin polypeptides in human gastric carcinomas

Phenotypic expression of keratin polypeptides is known to be dependent on various factors, one of which is malignant transformation. In this study, we compared the pattern of expression of keratin polypeptides between control and malignant gastric tissues by employing different morphological and biochemical techniques. The results indicated preferential decrease of acidic keratin polypeptides in malignant gastric tissues. The nonmalignant gastric tissues expressed four keratin polypeptides-two acidic and two basic-whereas in the gastric adenocarcinomas expression of only two basic polypeptides was observed. Marked variation of keratin expression between the control and malignant gastric tissues not only highlights its clinical value as a support to diagnosis but also elucidates the underlying changes due to malignant transformation.