Integrin-linked kinase (ILK), a
serine/threonine protein kinase, implicates in cellular control of cell-matrix interactions and cell proliferation that is associated with a highly invasive phenotype of certain
tumors. To study whether ILK is involved in the development and progression of gastric
carcinoma, we examined the expression of ILK in gastric
carcinoma cell lines, primary gastric
carcinomas and corresponding non-neoplastic mucosa using reverse-transcription polymerase chain reaction (RT-PCR) and immunohistochemistry and analyzed the relationship with clinicopathological parameters. The expression of ILK
mRNA was detected in 4 of 5 gastric
carcinoma cell lines and 22 of 35 (63%) microdissected
tumor samples of primary gastric
carcinoma using RT-PCR. The incidence of cases with ILK
mRNA expression was significantly higher in scirrhous and intermediate type (82%) than in medullary type (44%) (P=0.0204). Significant association was detected between ILK
mRNA expression and presence of nodal
metastasis (P=0.0388). Immunohistochemically, strong expression of ILK
protein (over 50% of
tumor cells were positive) was detected in 69% (84/122) of primary gastric
carcinomas, whereas no ILK expression was found in non-neoplastic gastric epithelia. Strong expression of ILK
protein was significantly associated with scirrhous and intermediate type (P=0.0217), deep invasion of
tumor cells in gastric wall (P=0.0006), and presence of nodal
metastasis (P=0.0176). These results strongly suggest that ILK may participate not only in stomach
carcinogenesis especially of scirrhous and intermediate types but also in invasion and
metastasis of gastric
carcinoma. ILK might be a novel molecular marker for aggressive
gastric cancer.