Table 2 shows that, of the 15 unique conserved positions where βIII differs from the βI, βIIA, βIIB, βIVA, and βIVB isotypes, human βVI only resembles βIII at five positions, of which four are positions where the other β isotypes mutated to resemble βIII in the breast cancer study. This evidence concerns the gene CACNA1B and breast carcinoma.