TM4SF1 knockdown significantly induced PARP (poly (ADP-ribose) polymerase) cleavage and up-regulated caspases 7, 9, and 3, suggesting that TM1SF4 promotes lung cancer cell apoptosis and may induce lung cancer cell resistance to chemo-therapy-induced apoptosis, and play a part in lung cancer chemo-resistance. Here, CASP7 is linked to lung cancer.