Expression of STEAP-1 and p40 in Prostatic Carcinoma and Its Mimickers: An Immunohistochemical Study

Prostatic carcinoma is the second most common cancer in men with high incidence of morbidity and mortality. It is a common health problem. Most cases occur at the age of 50 years, reaching its peak at 60-70 years of age. Diagnosis of prostatic carcinoma is still a problematic issue as accurate diagnosis can be very challenging due to the presence of either a small focus of cancer or the presence of many benign mimickers of malignancy.

Six transmembrane epithelial antigen of the prostate 1 (STEAP-1) is primarily localized at the cell membrane, mostly at cell-cell junctions, but it may also be found dispersed in the cytoplasm. In prostate, the expression of STEAP-1 is higher in neoplastic tissues compared to its restricted expression in normal prostatic samples.

The antibody designated as p40 recognizes exclusively ΔNp63 and not TAp63. In prostate tissues, it has been shown that p40, the ΔNp63 isoform of p63, stains prostatic basal cells as reliable as p63 in most cases. Furthermore, aberrant staining of tumor cells was seen more rarely with p40 than with p63.

In this study, the investigators hope to solve some problematic issues in diagnosis of prostatic carcinoma and reach the better way to distinguish prostatic carcinoma from mimicking lesions by using both STEAP-1 and p 40. Also, the way to detect cancer at early stage of development and its progression which is extremely important as it allows establishing the most effective treatment and predicting patient's outcome.