In the current study, we found no evidence of the BRAF, KRAS, NRAS, or PIK3CA mutations in rectal carcinoid tumors, suggesting that neither the RAS/RAF/MEK/ERK pathway nor the PI3K/AKT pathway were associated with tumorigenesis and disease progression in those tumors. The gene discussed is PIK3CA; the disease is rectal neuroendocrine tumor G1.