Evaluation of putative molecular biomarkers in abdominal and retroperitoneal leiomyosarcomas

Aims: Leiomyosarcomas (LMS) are diverse rumours with different biological b ehaviour. To evaluate the biological nature of intraabdominal and retroperi toneal leiomyosarcomas we retrospectively examined the immunoreactivity of p53, bcl-2 and proliferative activity expressed as Ki-67-labelling index in 43 tumours. Methods: Immunohistochemical staining was performed using a peroxidase-stre ptavidin method on paraffin-embedded sections using specific anti-p53, anti -bcl-2 and anti Ki-67 monoclonal antibodies. Results: Of 43 tumours, seven were located in the stomach, 11 in the small or large bowel, 12 in the uterus, 11 in the retroperitoneum and two cases i n the urinary bladder. Five-year disease-free survival was 46.5%. Twenty-th ree patients (53.4%) died of the disease. Positive immunoreactivity for p53 and bcl-2 was found in 18 (41.9%) and 26 patients (60.5%), respectively. P ositive Ki-67 staining was observed in eight patients (18.6%). Proliferativ e indices were higher in LMS with high mitotic activity (P=0.004) and high grade (P=0.009). All Ki-67 positive LMS were intermediate or high-grade tum ours. Ki-67-labelling index showed inverse relationship to bcl-2 expression . A trend towards higher survival and expression of bcl-2, p53 or Ki-67 was found. Conclusions: Our results demonstrate that p53 and bcl-2 are expressed in a substantial number of intraabdominal and retroperitoneal leiomyosarcomas. I n our study, the expression of these biomarkers did not predict patient out come. Higher Ki-67 labelling indices were found in more biologically aggres sive leiomyosarcomas. (C) 2001 Harcourt Publishers Ltd.