E-cadherin expression in the primary tumors and metastatic lymph nodes of poorly differentiated types of rectal cancer.

Abstract

Dysfunction of E-cadherin, a cell-cell adhesion molecule, correlates with the grade of dedifferentiation and/or invasiveness of rectal cancer. However, the relationship between E-cadherin expression in the primary tumor and the potential for metastasis has never been reported. E-cadherin expression in 43 primary rectal cancer, including 10 poorly differentiated type, and their associated metastatic lymph nodes (LN mets.) were immunohistochemically evaluated. Heterogeneous immunostaining, suggestive of damage to the E-cadherin-mediated cell-cell adhesion system, was seen in 13 of the 28 LN mets positive primary lesions, but in 0 of the 15 LN mets negative primaries. Furthermore, the incidence of heterogeneous immunostaining differed significantly between poorly differentiated and differentiated cancers, being seen in 8 of 10 cases and 5 of 33 cases, respectively (P = 0.0003 by Fisher's exact test). Interestingly, most of the LN mets. foci (25 of 28 cases) showed homogeneous staining regardless of the E-cadherin staining pattern of the primary lesion. Heterogeneous immunostaining of E-cadherin in poorly differentiated rectal cancer was associated with lymph node metastasis. Its staining pattern in metastatic lymph nodes were, however, generally homogenous.