We immunohistochemically analyzed
kallikrein 4 protein (hK4) expression in patients with
epithelial ovarian carcinoma (181 malignant effusions and 103 solid
carcinoma lesions). Expression of hK4 was also studied in 32 effusions using immunoblotting.
Carcinoma cells expressed hK4 in 144 (79.6%) of 181 effusions and 85 (82.5%) of 103 solid
tumors. Expression was seen in 51% or more of
tumor cells in 70 effusions but often was limited to 5% or fewer cells in solid
tumors (P = .009, primary
tumors vs effusions; P = .002,
metastases vs effusions). Immunoblotting showed hK4 expression in 31 of 32 specimens. Stromal cell hK4 expression, seen in 48 (46.6%) of 103 lesions, was significantly higher in primary
tumors than
metastases (26/43 vs 22/60, P = .019). hK4 expression in
tumor cells was significantly lower in International Federation of Gynecology and Obstetrics stage IV than stage III
tumors (P = .004, all lesions; P = .012, primary
tumors). hK4 expression in
carcinoma cells was associated with longer overall survival (not significant; P = .14, peritoneal effusions). hK4 is expressed widely in ovarian
carcinoma; levels in
carcinoma cells are highest in effusions, which might be related to loss of stromal contribution and/or altered microenvironment. hK4 expression in
carcinoma cells of effusions or solid
tumors does not predict survival.