Although there are several that are seen thousands of times, mostly due to a predominance of tumours driven by well-known cancer driver genes (e.g. JAK2 p.Val617Phe, EGFR p.Leu858Arg, KIT p.Asp816Val, BRAF p.Val600Glu/Lys), nearly half (54/110) of both activating and resistance variants are seen with counts of 50 or fewer; just under a third (33/110) are seen with 10 counts or fewer (Additional file 4: Table S16). Here, BRAF is linked to cancer.