High-grade prostatic intra-epithelial neoplasia (PIN) has been accepted as the main precursor lesion to invasive adenocarcinoma of the prostate, and this is likely to be the case. However, in an unknown number of cases, lesions fulfilling the diagnostic criteria for high-grade PIN may actually represent intra-acinar or intra-ductal spread of invasive carcinoma.
Intriguingly, this possibility would not contradict many of the findings of previous epidemiological studies linking high-grade PIN to carcinoma or molecular pathological studies showing similar genomic (e. g. TMPRSS2-ERG gene fusion) as well as epigenomic and molecular phenotypic alterations between high-grade PIN and carcinoma. Also, this possibility would be consistent with previous anatomic studies in prostate specimens linking high-grade PIN and carcinoma in autopsy and other whole prostate specimens. In addition, if some cases meeting morphologic criteria for PIN actually represent intra-acinar spread of invasive carcinoma, this could be an important potential confounder of the interpretation of past clinical trials enrolling patients presumed to be without carcinoma, who are at high risk of invasive carcinoma. Thus, in order to reduce possible bias in future study/trial designs, novel molecular pathology approaches are needed to decipher when an apparent PIN lesion may be intra-acinar/intra-ductal spread of an invasive cancer and when it truly represents a precursor state. Similar approaches are needed for lesions known as intraductal carcinoma to facilitate better classification of them as true intra-ductal/acinar spread on one hand, or as precursor high-grade PIN (cribriform type) on the other hand, a number of such molecular approaches are already showing excellent promise.
Cancer prevention research (Philadelphia, Pa. ). 2016 Jan 26 [Epub ahead of print]
Angelo M De Marzo, Michael C Haffner, Tamara L Lotan, Srinivasan Yegnasubramanian, William G Nelson
Department of Pathology, Johns Hopkins University Oncology, The Johns Hopkins University School of Medicine. , Department of Pathology, Johns Hopkins University School of Medicine. , Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine. , Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine.