Prostate cancer with 60,000 new cases a year is a public health problem which requires adapted and effective responses. The era of PSA screening dramatically increased the number of prostate biopsies that pathologists have to screen and consequently the number of difficult cases requiring analysis. Immunohistochemistry with anti-AMACR/p504s is useful for detecting prostate cancer in the full range of prostate specimens encountered in needle biopsies. In particular, studies to date with AMACR/p504s clearly demonstrate the ability of this marker to support a diagnosis of malignancy in prostate needle biopsies, combined with negative staining for a basal cell marker, such as p63. This study conducted by the Prostate Committee of the French Association of quality assurance in pathological anatomy and cytology (AFAQAP), reports the evaluation of the current practices with available anti-p63 and -p504s antibodies. The results of this investigation show a correct evaluation of the immunostaining procedure. Overall, from the 39/56 structures tested, the value of the test was positive in 85%. The best results were obtained after antigenic restoration with TRIS-EDTA pH 9, p504s (13H4, 1/200) and p63 (A4A, 1/100).