Objective: signet ring carcinoma of the stomach is well known to be more aggressive and infiltrating than adenocarcinoma. Different studies have proposed that signet ring cell carcinoma would be more infiltrating because of the lost of E-cadherin expression, this cadherin is a class of protein cell membrane protein which plays an important role in cell-adhesion. Methods: we carried out a transversal comparative study, in order to measure the E-cadherin expression in 10 cases of signet ring cell and in 10 cases of adenocarcinoma, with help of immunohistochemistry. Results: we found a bigger expression of E-cadherin in adenocarcinomas (100%) than signet ring cell carcinoma (40%), this difference was significative using Fisher test (p = 0,011). The lost of E-cadherine would explain the bigger infiltrating capacity in comparison to adenocarcinoma. Copyright © 2007 Arán Ediciones, s. l.