It is widely recognized that
matrix metalloproteinases and
serine proteinases play an important role in
cancer invasion and
metastasis. We have reported that
trypsin is synthesized in ovarian
carcinomas as well as in some other types of
cancers. In general,
ovarian cancers easily tend to invade, metastasize, and spread widely into the peritoneal cavity. However, low-malignant-potential (LMP, borderline
tumor) ovarian
tumors are known to have limited malignant potential for progression, although microinvasion and distant
metastasis have been reported among them. To analyze the relationship between varied degrees of
trypsin expression and malignant behavior of ovarian
tumors, immunohistochemical studies with
monoclonal antibodies to human
trypsin and clinicopathologic analysis were performed in human ovarian
carcinomas, low-malignant-potential
tumors, and benign
cystadenomas. Thirteen (44.8%) cases of 29 ovarian
carcinomas showed prominent
trypsin expression, while only 2 (18.2%) cases of 11 LMP ovarian
tumors demonstrated low levels of expression. Benign
tumors and normal ovaries did not show any positivity for
trypsin. These data suggest that
tumor-derived heterotropic
trypsin may be associated with ovarian
tumors in parallel with malignant potential or behavior such as invasiveness or
metastasis. At least in some ovarian
carcinomas, prominent stromal invasion or
metastasis might require the acquisition of or association with
tumor-derived
trypsin production.