PTK2 and neoplasm: To determine if the observed cisplatin-increased ERK activation in peritoneal protein lysates of FAK-NLS− tumor-bearing mice was a tumor cell–intrinsic response, KMF FAK-WT and KMF FAK-NLS− cells were treated with cisplatin (20 μmol/L for 12 hours) and lysates immunoblotted for total and active ERK (Fig. 6A).