DNA quantitation of intraepithelial neoplasia and invasive carcinoma of the prostate.

The relation of prostatic intraepithelial neoplasia (PIN) or ductal dysplasia and the development of invasive prostate cancer is not clear. PIN, especially high grade, is usually associated with coexisting invasive cancer. Although some investigators have identified micro foci of invasive cancer evolving from PIN, the two are usually anatomically separated. Because of these distinct anatomic patterns, many investigators have concluded that PIN represents a "field effect" or marker of potential cancer progression, and is not directly involved in or leads to the development of invasive prostate cancer. We measured the DNA content in 49 foci of invasive cancer and 87 foci of PIN identified in 34 radical prostatectomies containing both PIN and invasive cancer. In addition, we examined 13 prostatectomies and 5 TUR specimens containing only PIN. We found that the majority of low grade PIN had normal or diploid range DNA and that approximately half of the high grade PIN were abnormal or aneuploid. Prostates with coexisting diploid range PIN and invasive cancer had an approximately equal number of diploid range and aneuploid invasive cancers. Conversely, almost all of the aneuploid PIN (usually high grade) had coexisting aneuploid invasive cancers. This would support the hypothesis that events in the progression of prostate cancer may be operative in both the development of PIN and invasive cancer.