COEXPRESSION OF OSTEOPONTIN AND CD44V9 IN GASTRIC-CANCER

We have examined the expression of osteopontin (OPN) in 40 human prima ry gastric carcinoma tissues, 5 metastatic foci (lymph nodes) and corr esponding normal mucosas, Twenty nine of 40 primary tumors (72.5%) and 3 of 5 lymph node metastases (60%) overexpressed OPN mRNA in comparis on with those of the corresponding normal mucosa, The incidence as wel l as relative expression level of OPN mRNA was higher in well differen tiated gastric cancers than poorly differentiated ones. Moreover, incr eased OPN mRNA expression in primary tumor specimens was observed alon g with the advancement of the clinico-pathological stage. Using in sit u hybridization (ISH) analysis, not only inflammatory cells in tumor s troma but also tumor cells showed positive signals for OPN mRNA, By im munohistochemistry, co-immunoreaction of OPN and CD44v9 in tumor cells obviously correlated with the degree of lymphatic vessel invasion or long distant lymph node metastases in poorly differentiated gastric ca ncer. Interestingly, strong co-immunoreaction of OPN and CD44v9 of tum or cells was concommitant with cluster formation in the lymphatic vess els. Our results suggest that overexpression of OPN correlated with th e progression of human gastric carcinoma. Especially in CD44-bearing p oorly differentiated gastric cancer, interaction between OPN and CD44 may parallel lymphogenous metastasis. (C) 1998 Wiley-Liss, Inc.