The plots generated based on data obtained from the NCI-60 cancer cell line panel [23] and the Cancer Cell Line Encyclopedia (CCLE) [24] show that while the number of copies of the H2AX gene roughly correlates with the number of mRNA transcripts (correlation coefficients of 0.75 for NCI-60 and 0.45 for CCLE), the association is not strong enough to accurately predict H2AX protein expression based on gene copy number in tumor cells (S1A and S1B Fig). Here, H2AX is linked to cancer.