OBJECTIVES: To clarify the clinical and prognostic significance of cortactin and phosphorylated cortactin in patients with sarcomatoid renal cell carcinoma (SRCC). METHODS: We retrospectively reviewed the data from 31 patients with SRCC and 33 with conventional renal cell carcinoma matched for clinicopathologic features. The immunoreactive score for cortactin, pY421 cortactin, and pY466 cortactin were measured using immunohistochemistry. The relationships between each immunoreactive score and the clinicopathologic features and survival were investigated. RESULTS: The immunoreactive score of p421 cortactin, but not that of cortactin and pY466 cortactin, was significantly greater in SRCC than in conventional renal cell carcinoma (P < .001). The expression of pY421 cortactin in SRCC correlated with the pT stage and metastasis (P < .001). The expression of pY466 cortactin showed a similar trend with pT stage (P = .043) but not with metastasis. Although both of pY421 cortactin and pY466 cortactin were identified as useful predictors for survival in univariate analyses, only pY421 cortactin expression was considered an independent predictor in patients with SRCC (odds ratio 4.53, 95% confidence interval 1.07-19.12, P = .040) in the multivariate analysis model, including pT stage and metastasis. CONCLUSIONS: Our results have demonstrated that phosphorylation of cortactin is a key process in malignant aggressiveness, and its expression is a useful predictor of cause-specific survival and could be a useful potential therapeutic target in patients with SRCC.
OBJECTIVES: To clarify the clinical and prognostic significance of cortactin and phosphorylated cortactin in patients with sarcomatoid renal cell carcinoma (SRCC). METHODS: We retrospectively reviewed the data from 31 patients with SRCC and 33 with conventional renal cell carcinoma matched for clinicopathologic features. The immunoreactive score for cortactin, pY421 cortactin, and pY466 cortactin were measured using immunohistochemistry. The relationships between each immunoreactive score and the clinicopathologic features and survival were investigated. RESULTS: The immunoreactive score of p421 cortactin, but not that of cortactin and pY466 cortactin, was significantly greater in SRCC than in conventional renal cell carcinoma (P < .001). The expression of pY421 cortactin in SRCC correlated with the pT stage and metastasis (P < .001). The expression of pY466 cortactin showed a similar trend with pT stage (P = .043) but not with metastasis. Although both of pY421 cortactin and pY466 cortactin were identified as useful predictors for survival in univariate analyses, only pY421 cortactin expression was considered an independent predictor in patients with SRCC (odds ratio 4.53, 95% confidence interval 1.07-19.12, P = .040) in the multivariate analysis model, including pT stage and metastasis. CONCLUSIONS: Our results have demonstrated that phosphorylation of cortactin is a key process in malignant aggressiveness, and its expression is a useful predictor of cause-specific survival and could be a useful potential therapeutic target in patients with SRCC.