RAPGEF5 and cancer: Blockage of the GFR signaling pathway via application of prominent anti-cancer drugs, such as sorafenib (RAF inhibitor), RO5126766 (dual RAF/MEK inhibitor), pictilisib (PI3K inhibitor), and omipalisib (dual PI3K and mTOR inhibitor), effectively prevents SARS-CoV-2 replication in cellular models.