Loss of p21WAF1/Cip1 protein expression accompanies progression of sporadic colorectal neoplasms but not hereditary nonpolyposis colorectal cancers.

p21 (p21WAF1/Cip1), a cyclin-dependent kinase inhibitor, induces G1 arrest and can inhibit the activity of the proliferating cell nuclear antigen (PCNA). We analyzed p21 expression during colorectal tumorigenesis, its association with its transcriptional regulator p53, and its relationship to rates of cell proliferation and apoptosis. p21 and p53 protein expression were examined in sporadic tumors and hereditary nonpolyposis colorectal cancers (HNPCCs) by immunohistochemistry (IHC) and immunoblotting. Apoptosis was examined using a DNA nick end-labeling assay, and cell proliferation was examined by PCNA staining. In normal colorectal epithelia, nuclear p21 staining was uniformly detected in crypt cells of the superficial compartment (upper one-third) that stained negatively for PCNA. p21 and PCNA expression were, therefore, mutually exclusive. In sporadic cases, a decrease in the frequency of p21 expression accompanied adenoma development and progression to carcinoma. Specifically, p21 was detected in 12 of 16 (75%) adenomas and 10 of 32 (31%) carcinomas. In contrast to sporadic cases, HNPCCs with known mutations in DNA mismatch repair genes expressed p21 in 12 of 15 (80%) carcinomas. An inverse relationship between p21 and p53 was observed wherein mutant p53 proteins were detected in 4 of 15 (27%) HNPCCs versus 22 of 32 (69%) sporadic carcinomas. Although p21+ carcinoma cells were generally negative for p53, IHC revealed that some carcinoma cells expressed both p21 and p53 proteins. Furthermore, p53-mutated SW480 colon carcinoma cells were found to coexpress p21 and p53, suggesting that p21 can also be activated by a p53-independent mechanism. No association was found between p21 or PCNA and apoptotic labeling indices in adenomas or carcinomas. In conclusion, a decrease in p21 expression accompanies neoplastic progression in sporadic cases but not in HNPCCs. This finding appears related to p53 status in that the frequency of p53 expression was significantly reduced in HNPCCs compared to sporadic cases, suggesting a difference in their molecular pathways of tumorigenesis.

Increased apoptosis accompanies neoplastic development in the human colorectum.

A disturbance in the balance between cell proliferation and cell loss, or apoptosis, may underlie neoplastic development. Therefore, we determined spontaneous apoptotic and proliferative rates in normal, hyperplastic, adenomatous, and malignant colorectal epithelia. In paired sections, DNA strand breaks were detected using the terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay, and apoptotic cells were also identified in H&E-stained slides by morphological criteria. Cell proliferation, bcl-2, and p53 expression were analyzed using specific monoclonal antibodies. In normal mucosa, luminal epithelial cells demonstrated higher rates of apoptosis compared to cells in the proliferative zone. Neoplastic transformation was associated with a significant increase in rates of apoptosis and proliferation. However, apoptosis, but not proliferation, decreased at the adenoma-to-carcinoma transition coincident with expression of mutant p53. In carcinomas, both mutant p53 and bcl-2 protein levels were associated with attenuated apoptotic rates. In conclusion, apoptosis is an important regulator of growth in normal and neoplastic colorectal epithelia. Increased apoptosis and proliferation accompany neoplastic transformation, suggesting that an alteration in apoptotic rates is an important event in colorectal carcinogenesis. Furthermore, the imbalance in these processes found in carcinomas may facilitate tumor growth and progression.

Enhanced intramucosal cytotoxic lymphocyte gene expression in ulcerative colitis.

: The histopathology of the mucosal lesions in ulcerative colitis suggests that cellular immune hyperactivity plays a role in the pathogenesis of ulcerative colitis. The role of colonic mucosal cytotoxic lymphocytes in ulcerative colitis is highly controversial. In vitro determinations of cytotoxic lymphocyte function vary according to the experimental conditions and target cells employed. Transcription of the cytotoxic molecules granzyme B and perforin are specific for activated cytotoxic lymphocytes. We investigated whether activated cytotoxic lymphocytes are present in ulcerative colitis lesions via identification of granzyme B, perforin, and interleukin 2 transcripts. RNA was extracted from endoscopic colonic biopsies taken from normal and ulcerative colitis patients. An aliquot was reverse transcribed, followed by gene amplification in the polymerase chain reaction. A competitive template was incorporated within the reaction permitting the quantitation of specific mRNA species. Granzyme B and perforin levels of reverse transcribed cDNAs (RT-cDNAs) were significantly elevated in active ulcerative colitis as compared to normal colonic tissues (p = 0.0081 and p = 0.0018, respectively) when calculated as a ratio with the RT-cDNA of the constitutively expressed gene GAPDH. Interleukin 2 mRNA measurements did not vary between normal and UC samples to a statistically significant degree. These data suggest heightened lymphocyte cytotoxic function within ulcerative colitis mucosal lesions.

Language patterns of opponents to a child protection program.

A community effort was made to help sexually abused girls and a "pro-incest lobby" was uncovered. This report focuses on the language used to deny or obscure the occurrence of father-daughter incest. As children's rights advocates, the authors attempted to provide a lexicon, a dictionary for the clinician, so that efforts to condone incest will not be overlooked but refuted. Both in the past and the present, instances of incest have been rationalized away by health care professionals, members of the legal profession and the community at large. The incidence of incest is higher than the increasing number of actual cases reported. The vocabulary that systematically drives certain resistances and defenses to the surface, in opposition to child protection in such cases, is analyzed by the authors. The "dynamics" involved in the realization of incest as a psychologically damaging situation for the child are complex. The social influences on the individual and the married couple, that serve to make incest a closely kept secret, are examined. The authors express hope that their linguistic analysis will help to alert all persons who work in the broad field of child abuse and child protection.