Fig. 1: RNAi screening and Kaplan-Meier plot strategies to identify DNA damage repair regulators of TNBC.

A The schematic diagram highlights the criteria for gene selection and the experimental setup for the RNAi screen. ^#1890 DDR-related genes were identified based on the CRISPR-Cas9 screens against 27 genotoxic agents¹⁸. ^#2 The top 500 overall-survival-related genes were directly downloaded through GEPIA portal based on the TCGA-BRCA database⁴⁵. B The heat map that represents the expression of selected genes in different BC cells was determined by qPCR analysis. C The bar chart shows the average Z-score of TNBC cell lines minus the average Z-score of luminal cell lines (ΔZ-score) for all the genes included in the RNAi screen. A negative value indicates that the siRNA decreased the HR/NHEJ ratio more in the TNBC cell lines (*P < 0.05 comparing TNBC and luminal Z-scores). Data were analyzed by a two-tailed t test. D The average TNBC (T) and luminal (L) Z-scores for all cell lines for CXorf56. The P-value (****P < 0.0001) indicates a statistically significant difference between TNBC and luminal lines. Data were analyzed by a two-tailed t test. E The difference in CXorf56 transcript levels between normal breast and cancer tissues is presented as a scatter dot plot. Data were analyzed by a two-tailed t test. Scatter dot plots show the transcript levels of CXorf56 across the breast cancer subtypes based on the IHC (F) or PAM50 (G) classification of the TCGA-BRCA cohort. Data were analyzed by a two-tailed t test. H Kaplan-Meier survival curve shows a poorer OS rate in BC patients with high CXorf56 transcript levels than those with low CXorf56 transcript levels. Data were analyzed by a log-rank test. Remarks: *p < 0.05, **p < 0.01, ***p < 0.001, ****P < 0.0001; Data are presented as mean ± SD.