COX-2, NSAIDs and human neoplasia. Part I: Colorectal neoplasms.

Cyclooxygenase-2 (COX-2), the inducible cyclooxygenase isozyme involved in the conversion of arachidonic acid (AA) to biologically active prostanoids, has become the subject of intense interest during the last few years. The recent surge of interest stems from seminal studies that correlated elevated expression of COX-2 with tumor induction and progression, and epidemiological studies that correlated reduced risk of developing certain types of cancers with chronic use of non-steroidal anti-inflammatory agents (NSAIDs). Although these observations were first reported with colorectal cancer (CRC), similar findings have subsequently been made with other types of cancers. A wide spectrum of studies continue to be undertaken in both laboratory and clinical settings to elucidate the mechanisms underlying these anti-tumor effects of COX-2 for potential translation into cancer chemoprevention and therapy. The aim of this article is to present a review of COX genes, the prostaglandin-cyclooxygenase relationship, the role of COX-2 in carcinogenesis and the rationale for targeting COX-2 with NSAIDs for cancer chemoprevention. Special emphasis is given to the role of COX-2 expression in the genesis and progression of colorectal neoplasia, and its correlation with other pathological characteristics of CRC. Preliminary observations on COX-2 expression in inflammatory bowel disease (IBD)-related colorectal neoplasia are also presented.

Preneoplastic lesions of the prostate-clinical, pathological and molecular biological aspects.

Needle biopsy is the mainstay of definitive diagnosis of prostate cancer (PCA). While prostate-specific antigen (PSA) screening has facilitated early diagnosis of PCA, it has also resulted in an increase in the proportion of prostate biopsies showing various preneoplastic lesions (PNLs). At times such lesions are the sole finding in the limited amount of tissue available for assessment in an individual biopsy. Hence accurate identification of these lesions is important to avoid errors in the diagnosis of prostatic malignancy and in patient management. Furthermore, some interesting observations have been made regarding the molecular biological aspects of various PNLs during the last decade. In parallel with anatomic and physiological differences in various human races, racial differences have also been observed regarding the incidence of prostatic intra-epithelial neoplasia. This review focuses on prostatic intraepithelial neoplasia (PIN), atypical adenomatous hyperplasia (AAH) and atypical prostatic glands or atypical small acinar proliferation (ASAP) as putative preneoplastic lesions of the prostate. These lesions are reviewed with reference to their overall incidence, histopathological findings, histological differential diagnosis, clinical significance and molecular biological aspects.