The Prognostic Implications of the Histologic Subtype and the Expression of Phosphorylated ERK 1/2 in Papillary Renal Cell Carcinoma

ABSTRACT

BACKGROUND: The authors of this study wanted to confirm the prognostic implication of the histologic subtype; further, we wanted to explore the expression of phosphorylated extracellular signal-regulated kinase 1/2 (pERK) in papillary renal cell carcinoma (PRCC) and determine its clinicopathologic and prognostic significance. METHODS: A total of 45 patients who underwent nephrectomy for PRCC were enrolled in this study. The hematoxylin and eosin slides were reviewed and pERK immunohistochemistry was performed. RESULTS: Type 2 PRCC was significantly correlated with a larger tumor size (p=0.030), a higher nuclear grade (p<0.001), a more advanced tumor stage (p=0.041) and more frequent distant metastasis (p=0.019). The tumors were pERK-low (0 and 1+) in 30 cases (66.7%) and pERK-high (2+) in 15 cases (33.3%). The pERK-high PRCC was significantly associated with a smaller tumor size (p=0.001) and an earlier tumor stage (p=0.004). On the univariate analysis, the histologic subtype, the TNM stage and the pERK status were significantly associated with progression-free survival (PFS). Multivariate analysis showed that the histologic subtype (hazard ratio 22.81, p=0.042) and the TNM stage (hazard ratio 23.48, p=0.009) were independent prognostic factors for PFS. CONCLUSIONS: Type 2 PRCC, together with the TNM stage, was identified as one of independent poor prognostic factors for PFS. The pERK status was a prognostic factor for PFS on the univariate analysis, but not on the multivariate analysis.