These tumours all had a very low mutational burden, low HRDetect scores (0.03 or less) and a higher frequency of somatic PIK3CA mutations and a lower frequency of TP53 mutations compared to tumours with a high mutational burden (Fig. 1, Additional file 2: Figure S2, Additional file 8, 9: Table S4-S5). The gene discussed is TP53; the disease is neoplasm.