We initially studied the pancreas tumor cell line AsPC-1 which is acutely sensitive to both drugs, and investigated the concentration and time required to induce phosphorylation of RPA and H2AX (this phosphorylation on ser139 is known as γH2AX) which are commonly used as markers of single-stranded DNA and DSB, respectively (Figure 2A). Here, RPA1 is linked to neoplasm.