It was observed that elevated BRCA1 expression was capable of rescuing the decrease in CLL cell growth (Fig. 6H) and elevation in cell apoptosis causing by CTPS2 knockdown Fig. 6I. Moreover, immunofluorescence staining of p-H2AX (Fig. 6J) and comet assay (Fig. 6K, L) showed that overexpression of BRCA1 rescued CTPS2 shRNA-induced DNA damage elevation. Here, CTPS2 is linked to B-cell chronic lymphocytic leukemia.