Background: Alpha-methylacyl-coenzyme A racemase (AMACR, P504S) is a commonly used marker in immunohistochemical diagnosis of prostate cancer. Recent studies identified P504S markers of the clear cell histotype in the ovary and/or endometrium. Gastric-type adenocarcinoma (GAS) is difficult to diagnose histologically, particularly when there is crossover with clear cell carcinoma (CCC). However, the significance of P504S for differentially diagnosing GAS and CCC is unclear.
Aim: To evaluate P504S as a potential diagnostic marker of GAS and CCC.
Settings and design: We analyzed P504S expression in 48 cervical carcinomas (32 GAS and 16 CCC), as well as the expression of other markers including hepatocyte nuclear factor-1 beta (HNF-1β) and NapsinA.
Material and methods: The expression differences of HNF-1β, NapsinA, and P504S in GAS and CCC were detected by immunohistochemistry. Immunohistochemical histoscores based on the intensity and extent of staining were calculated.
Results: The positive rates of HNF-1β in GAS and CCC were 90.32% and 75%, respectively. (χ2 = 2.251, P = 0.663). The positive rates of NapsinA in GAS and CCC were 19.36% and 81.25%, respectively. (χ2 = 47.332, P < 0.01). The positive rates of P504S in GAS and CCC were 16.13% and 81.25%, respectively. (χ2 = 41.420, P < 0.01). HNF-1β was frequently expressed in GAS and CCC, while NapsinA and P504S were frequently expressed in CCC, and reduced or lost in GAS.
Conclusion: NapsinA and P504S can be used to differentiate between GAS and CCC.
Keywords: Alpha-methylacyl-CoA racemase; NapsinA; P504S; clear cell carcinoma; gastric-type adenocarcinoma; hepatocyte nuclear factor-1 beta.