Lack of ERG-antibody in Benign Mimickers of Prostate Cancer

Prostate carcinoma (PC) is the second most diagnosed cancer in men worldwide. Prostate tissue in needle biopsy expresses a wide variety of architectural patterns some of which are difficult to interpret. Immunohistochemical markers, such as AMACR, p63 and 34βE12 that are currently used in diagnosing prostate cancer, are of great value, but often their interpretation is ambiguous. In 2005 Tomlins et al. identified an emerging marker, erythroblastosis E26 rearrangement gene (ERG), which is a member of the family of genes encoding erythroblast-transformation specific transcription factors (ETS) with frequent expression in PC.

The aim of this study was to investigate the expression of ERG in benign mimickers of PC in needle biopsies and its diagnostic value alone and in combination with AMACK and 34βE12.

Of the selected 46 biopsies, two were eventually diagnosed as PC Gleason score 6 as they were simultaneously ERG and AMACR-positive and 34βE12-negative. One case was considered atypical. The remaining 43 biopsies were diagnosed as benign cases: simple atrophy in 13 cases, partial atrophy in 11, adenosis in 9, basal cell hyperplasia in 3, post-atrophic hyperplasia in 3, clear cell hyperplasia in 2 and sclerotic adenosis in 2 cases. None of the 43 benign cores showed evidence of ERG expression.

ERG could be preferably used in diagnosing prostate needle biopsies, lesions that are hard to interpret and controversial expression of AMACR/34βE12.