p53 immunohistochemistry for distinguishing reactive mesothelium from low grade ovarian carcinoma.

OBJECTIVE: To determine the utility of immunohistochemical staining for p53 in cell block material for distinguishing reactive mesothelium from borderline or low grade ovarian carcinoma. STUDY DESIGN: Paraffin-embedded cell blocks from paracentesis and pelvic wash fluid of 44 cases of ovarian carcinoma and 20 cases containing only reactive mesothelium were immunostained for p53 using monoclonal antibody DO-7. Tumor grades ranged from borderline to high grade and were serous papillary (33), clear cell (3), mucinous (2), endometrioid (2), mixed serous papillary/clear cell (3) and undifferentiated (1). The three authors independently evaluated the staining, including estimation of the percentage and intensity of positive nuclear staining. RESULTS: A separation of positive from negative cases was seen when staining intensity was considered the critical parameter; moderate to strong staining was considered truly positive. Seventy-three percent (8/11) of borderline tumors, 80% (8/10) of low grade tumors and 65% (15/23) of intermediate to high grade tumors showed moderate to strong positivity. Percentage of staining was a less-reliable parameter as 25% of negative cases were positive by this assessment. CONCLUSION: p53 Immunohistochemistry, using monoclonal antibody DO-7 combined with standard morphologic evaluation, may be useful in distinguishing benign reactive mesothelium from borderline or low grade ovarian carcinoma.

Expression of p21WAF1/CIP1 in soft tissue sarcomas: a comparative immunohistochemical study with p53 and Ki-67.

The p53 gene controls the cell cycle by transactivating p21WAF1/CIP1, a cyclin dependent kinase (cdk) inhibitor. By inhibiting cdks, p21WAF1/CIP1 regulates the cell cycle by blocking the G1 to S phase transition. In this study, we analyzed the immunohistochemical expression of p21WAF1/CIP1 in 66 soft tissue sarcomas and its relationship to p53 and the cell cycle proliferation antigen Ki-67. Expression of p21WAF1/CIP1, was detected in 76% of the tumors and p53 in 26%. All malignant schwannomas, synovial sarcomas, leiomyosarcomas and gastrointestinal stromal tumors expressed p21WAF1/CIP1. The majority of angiosarcomas, dermatofibrosarcomas, and fibrosarcomas showed low expression or were negative for p21WAF1/CIP1. Ewing's sarcomas, liposarcomas, and malignant fibrous histiocytomas were heterogeneous in their expression of p21WAF1/CIP1. Combining p53 and p21WAF1/CIP1 staining, the following four patterns were observed: 23% of the tumors showed the p53+/p21+ pattern; 53% showed the p53-/p21+ pattern; 3% showed the p53+/p21- pattern and 21% were negative for both p53 and p21WAF1/CIP1. There was no correlation between Ki-67 and p21WAF1/CIP1 or p53 staining. Our results show that soft tissue sarcomas, independent of their histologic subtype, frequently express p21WAF1/CIP1 which is probably important in their tumorigenesis. Additionally, p21WAF1/CIP1 may play a role in determining the efficacy of various cell cycle-directed therapies in soft tissue sarcomas.

Tumor-associated glycoprotein (TAG-72) in endometriotic implants.

Tumor-associated glycoprotein (TAG-72) is an antigen detected by the monoclonal antibody B72.3 that is expressed by a wide variety of human malignancies and in normal secretory endometrium. Serum TAG-72 may be elevated in women with endometriosis, but the distribution of TAG-72 in this disorder has not been well studied. Accordingly, TAG-72 was assayed by immunohistochemical staining in 26 endometriotic implants collected at various times of the menstrual cycle and compared to that in 56 samples of normal endometrium, in 8 cases from the same patient. TAG-72 expression was markedly discordant between normal and ectopic endometrium. Unlike proliferative phase endometrial samples, which were uniformly negative, endometriotic implants were TAG-72 positive in 50% of the cases. Like normal endometrium, all except very early secretory phase endometriosis was positive. Based on our current understanding of TAG-72 expression, this unique estrogen-repressed glycoprotein may be a useful probe to study the basis for phenotypic alterations noted in endometriosis, some of which probably contribute to the infertility associated with this disease. Moreover, the presence of B72.3 in nonmalignant tissues puts in question it usefulness in screening for malignancies.