HMOX1 and breast cancer: Consistently, the real-time PCR analysis confirmed that 4HC treatment led to a significant increase in Hmox-1 and Slc7a11 mRNA levels at an early stage (within 6 h) in the murine glioblastoma cell lines GL261, CT-2A, and KR-158 and the 4T1 murine breast cancer (Figure 1C).