Patterns of differentiation and proliferation in intraductal carcinoma of the prostate: Significance for cancer progression

BACKGROUND. Cribriform prostatic intraepithelial neoplasia (C-PIN) identifi es a unique histological pattern: dysplastic cells line ductal/acinar walls but also span across gland lumens. C-PIN is distinct from other forms of d ysplasia; it is seldom seen except within invasive cancer, it is more frequ ent in larger/higher-grade cancers; and it appears to contribute independen tly to aggressive behavior. Hence, C-PIN may represent a separate, more agg ressive entity: intraductal carcinoma of the prostate (IDC-P). Here, suppor t for that distinction stems from a histologic/biologic subclassification o f IDC-P, whose elements are linked to features of invasive cancer. METHODS. Histologic criteria were tested against 26 radical prostatectomies , using immunostains for prostate-specific antigen, MUC-2, androgen recepto r (differentiation), and Ki-67 (proliferation). Invasive cancer grade, stag e, and follow-up were compared. RESULTS. Architecture of the central (luminal) cell compartment defined thr ee subclasses of IDC-P: A (trabecular), B (cribriform), and C (solid/comedo ), which represented progressive dedifferentiation with a reciprocal increa se in proliferation. The IDC-P subpattern correlated with cancer stage, gra de, and clinical course. CONCLUSIONS. IDC-P is a separate entity, distinct from PIN; cancers associa ted with IDC-P are more aggressive than those associated with only PIN. It comprises a spectrum of histological patterns which appear to be determined in concert with invasive cancer, whose prognosis it worsens. Prostate 43:1 1-19, 2000. (C) 2000 Wiley-Liss, Inc.