Furthermore, we found that cancer cells exhibited dominant expression of the mutated alleles (Fig. 7D), including those in the proto-oncogene KRAS (e.g., c.35G>T in CRC07, c.436G>A in HTCRC01 and c.38G>A in HTCRC05), KLF5 (c.935C>T in CRC07) and PIK3CA (c.2836G>T in CRC09). This evidence concerns the gene PIK3CA and cancer.