Matrilysin is known to play an important role in
tumor invasion, but it is not known yet whether there is a direct relationship between
matrilysin expression and cell proliferation. Therefore, we compared expression of
matrilysin with expression of Ki-67, a marker of cell proliferation, at different
tumor areas in 130 advanced gastric
carcinomas. Both
matrilysin and Ki-67 were distributed heterogeneously in
tumor tissue.
Matrilysin frequently was expressed at the invasive front, whereas Ki-67-positive cells frequently were located both at the
tumor surface and in central
tumor cell nests. The patterns of
gastric cancer cell invasion into the surrounding tissues are described as alpha-infiltration, beta-infiltration, and gamma-infiltration, respectively, according to the guidelines of the Japanese Research Society for
Gastric Cancer Study. The mean
matrilysin labeling index (LI) of gamma-infiltration
tumors at the invasive front was significantly greater than that of alpha- and beta-infiltration
tumors (P =.01). In contrast to the
matrilysin LI, the mean Ki-67 LI of gamma-infiltration
tumors was significantly lower than that of alpha- and beta-infiltration
tumors (P =.02). Moreover,
Ki-67 antigen was absent in
matrilysin-positive
tumor cells and vice versa. We concluded that
matrilysin expression was related inversely with proliferative activity of
tumor cells and that
matrilysin expression could possibly serve as a useful marker of
tumor invasion.