PIK3CA and small cell carcinoma: These include additional mutations in EGFR (40–60%) [4, 6] and mutations in PIK3CA (5%) [7] and BRAF (1%) [8], amplification of MET (5–10%) [6, 9] and ERBB2 (12%) [10], phenotypic transformation such as to small cell carcinoma (3–14%) [6, 7] and the epithelial to mesenchymal transition [5, 7].