Evaluation of immunohistochemical parameters as prognostic markers in malignant fibrous histiocytoma.

In this study 65 primary malignant fibrous histiocytomas (MFH) of high malignancy grade were characterized by immunohistochemistry for their expression of proteins reflecting or promoting tumor growth. The results were evaluated in relation to the disease-free survival and the occurrence of metastases alone or in combination with local recurrences during follow-up. A tumor size >8 cm was strongly associated with both a shorter disease-free survival (p=0.001) and a higher frequency of metastases alone or together with local recurrence during follow-up (p=0.001 and 0.004). Similarly a higher frequency of mitosis was associated with a shorter disease-free survival (p=0.004), while the presence of necrosis or malignancy grade 4 did not affect the clinical outcome. No significant effect on the clinical outcome was seen for p53, Ki-67, p27 expression or for vascular density determined by factor VIII staining. However, a significant association was demonstrated between high Bcl2 expression and the risk to develop both local recurrence and metastases (p=0.026). Taken together, the findings support the importance of the tumor size, and suggest that bcl2 staining but not p53, Ki-67, p27, vascular density or distinction of grade 3 and grade 4 tumors are of clinical value in the prognostication of MFH tumors.