RAP2B and pulmonary arterial hypertension: Five (COMP, FGFR4, ITGA11, LPAR2, and PPP2R5A) of the nineteen RUNX2 target genes related to the PI3K-Akt signaling pathway are coexpressed in the CCP formed between lung cancer and PAH [12], and four (COL3A1, ITGA11, RAP2B, and PPP2R5A) of the nine RUNX2 target genes related to Wnt signaling pathway are coexpressed in the CCP formed between lung cancer and PAH, suggesting the importance of the RUNX2 regulatory function in these two signaling pathways in lung cancer establishment.