Leiomyosarcoma in soft tissue: examination of p53 status and cell proliferating factors in different locations.

The biological behavior of soft tissue leiomyosarcoma varies with its location: tumors in deep soft tissue show a worse prognosis than those in superficial soft tissue. In this study, we analyzed cell proliferating factors (mitotic and Ki-67 indices) and the p53 status of both types of leiomyosarcoma (37 cases) to evaluate the possibility that these factors may serve as indicators in prognosis. Expression of both of the cell proliferating factors were higher in the superficial type, but these differences were not significant. The incidence of abnormal p53 detected by immunohistochemistry and mutation analysis was also higher in the superficial type, but, again, no significant difference was observed. Abnormal p53 and a high Ki-67 index in the deep type, and a large tumor size (>6 cm) in the superficial type may be useful as prognostic factors. Interestingly, all of the superficial cases who died of the disease showed abnormal p53. In conclusion, these two types of leiomyosarcoma are essentially the same, and their location remains a good prognostic factor. Furthermore, abnormality of the p53 gene was related to a poor prognosis regardless of the tumor's anatomic location.