SCLC-P (POU2F3-dominant): Marked by high expression of POU Class 2 Homeobox 3 (POU2F3), this non-neuroendocrine subtype represents a distinct tuft-cell-like lineage and may be sensitive to Insulin-like Growth Factor 1 Receptor (IGF1R) inhibitors or other novel targeted agents. This evidence concerns the gene POU2F3 and small cell lung carcinoma.