Hsp70 inhibition induces the accumulation of p-eIF2α to a similar extent in MAL3-101 sensitive and resistant breast cancer lines, but the eIF2α kinases (PERK versus GCN2) and the final cellular outcomes (apoptosis versus autophagy, respectively) are distinct: PERK knockdown blunted the death response in sensitive cells after MAL3-101 treatment, whereas the silencing of GCN2 favored the death of resistant cells after the same treatment. Here, EIF2AK3 is linked to breast carcinoma.