PGP9.5 as a marker for invasive colorectal cancer.

Purpose And Experimental Design: We proved recently that PGP9.5-negative pancreatic cancer patients had significantly better survival rates compared with those who were PGP9.5 positive, and PGP9.5 may be a novel marker for indicating the prognosis of pancreatic cancer patients. In this study, we examined the expression of PGP9.5 in primary colorectal cancers using immunohistochemistry and correlated the result with the clinicopathological features.

Results: Of 74 colorectal cancer specimens examined, 33 cases (46%) showed positive staining with PGP9.5 in most tumor cells, whereas no PGP9.5 expression was detected in adjacent normal epithelium. Subsequently, we correlated PGP9.5 expression in tumors with the clinicopathological features of affected patients and found two significant differences in maximal tumor size and the extent of tumor (P = 0.035 and 0.019, respectively).

Conclusion: This result suggests that PGP9.5 expression is related to tumor progression and may be useful as a marker for invasive colorectal cancer.