GUCY2C and cancer: The overexpression of Guanylyl cyclase C (GCC) receptors on CRC cancer cells renders them a promising target, that can be efficiently exploited to increase PS internalization in targeted CRC cells, minimize the alteration on nearby healthy cells, thereby enhancing the overall efficacy of PDT (Winifred Nompumelelo Simelane and Abrahamse, 2021).