Immunohistochemical expression of cytokeratin 14 and association with the extent of squamous differentiation in urothelial carcinoma

Objective Evaluation of the diagnostic utility of cytokeratin 14 (CK14) immunostaining for squamous differentiation in urothelial carcinoma (UC). Background UC with squamous differentiation usually presents at an advanced stage than pure UC. Moreover, increased extent of squamous differentiation in UC tends to be associated with poor survival. Sometimes, immunohistochemical marker may be needed for diagnosis of squamous differentiation in UC. Materials and methods This retrospective cross-sectional study included 58 cases of radical cystectomy and 16 cases of cystoscopic biopsy diagnosed with bladder cancer. The cases included 16 cases of squamous cell carcinoma (SCC), 26 of pure UC, 31 of UC with squamous differentiation, and one case of adenocarcinoma. They were subjected to immunohistochemical staining for CK14. CK14 expression and its association with some clinicopathologic parameters were evaluated. Results CK14 showed positive expression in 74.2% of UC with squamous differentiation, 19.2% of pure UC, and all cases of SCC. It showed sensitivity of 74% and specificity of 81% for detecting squamous differentiation in UC. Its expression has significant association with the extent of squamous differentiation in UC (P = 0.001), perineural invasion (P = 0.03), and grade of SCC (P = 0.0001). Conclusion CK14 is a specific and sensitive marker in diagnosis of SCC and squamous differentiation in UC, and its expression is associated with poor prognostic parameters in bladder cancer.