E2F1 and cancer: In cancer-associated fibroblasts (CAFs) of small cell lung cancer (SCLC), a decrease in Cav-1 expression can upregulate the transcriptional activation of its downstream molecule E2F transcription factor 1 (E2F1) and the expression of mitophagy marker BCL2 interacting protein 3 (BNIP3), leading to metabolic changes and inducing metabolic reprogramming pathways in tumor cells (48).