Furthermore, as 5-HT-induced angiogenesis is suggested as an underlying mechanism of resistance to antiangiogenic therapy targeting VEGF due to the presence and involvement of 5-HT in the tumor microenvironment, inhibition of PI3K by BJ-1108 could be applied as an adjuvant therapy to anti-receptor tyrosine kinase therapy against cancer. The gene discussed is PIK3CD; the disease is cancer.