KRAS and ovarian benign neoplasm: Ras/p21 oncoprotein expression and K-ras mutations were analysed by Western blot and/or K-ras oligonucleotide hybridization in 78 primary ovarian cancers, 20 omental metastases, two low malignant potential tumours (LMP), nine benign ovarian tumours and 10 normal ovaries.