Sutthiporn Namnak, BSc *, Wipawee Kittikowit, MD *, Jutamas Wongphoom, BSc* *Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand Correspondence to: Wipawee Kittikowit, MD Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
Objectives: To determine the validity of immunohistochemistry in classifying Renal cell carcinoma (RCC) subtypes. Methods: Eighty-three cases of RCC were retrieved. Immunohistochemical staining of Vimentin, CD10, CK7, P504s, Parvalbumin, TFE3, and CD117 were done by using tissue microarray blocks. RCC subtypes were placed and compared with the previous diagnosis.
Results: Seventy-eight of 83 cases showed agreement with the original diagnosis. Vimentin expressions were observed in Clear cell RCC(CRCC) and Papillary RCC(PRCC). CD10 staining was detected in CRCC (82%) and in PRCC (77%) and Chromophobe RCC (CHRCC) (50%). CK7 was positive in all cases of CHRCC, and negative in 93% of CRCC. P504s was expressed in 88% of PRCC and negative in 96% of CRCC and 84% of
CHRCC. Parvalbumin was expressed in 32% of CHRCC, and negative in all CRCC and PRCC. CD117 was positive in all CHRCC and negative in CRCC and PRCC. TFE3 was negative in all cases.
Conclusion: The expression patterns of the IHC markers in RCC subtypes were concluded. Vimentin, CD10 and CK7 were suggested as the first-stepped IHC markers. CD117, Parvalbumin, and P504s were suggested as the second stepped IHC markers to confirm the diagnosis.