Loss of expression of α4β7 integrin and L-selectin is associated with high-grade progression of low-grade MALT lymphoma

Abstract

Expression of adhesion molecule in low-grade B-cell mucosa-associated lymphoid tissue (MALT) lymphoma of the gastrointestinal tract has been reported in recent years, but these reports have primarily focused on low-grade gastrointestinal MALT lymphoma. In this study, we examined the lymphocytic homing receptor α4β7 integrin, L-selectin, and VLA-4 and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in low-grade lymphoma of the gastrointestinal tract and other organs such as the ocular adnexa and thyroid. We also observed changes in the expression pattern associated with high-grade transformation. Neoplastic cells in the gastrointestinal low-grade lymphoma and the low-grade component of high-grade MALT lymphoma were found to be α4β7 integrin+, L-selectin+, whereas the gastrointestinal high-grade component and diffuse large B-cell lymphoma were found to be α4β7 integrin-, L-selectin-. High endothelial venules in the gastric MALT lymphomas expressed MAdCAM-1. In the ocular adnexa low-grade MALT lymphoma, most cases were α4β7 integrin-, L-selectin+; and in the thyroid, most cases of both low- and high-grade MALT lymphoma were α4β7 integrin-, L-selectin-. These findings show that α4β7 integrin and L-selectin may play an important role in the lymphocyte homing of gastrointestinal low-grade MALT lymphoma and in the loss of α4β7 integrin expression throughout the course of high-grade progression.