First, we analyzed normalized mRNA transcript levels of SLC7A11 and SLC3A2 from data from The Cancer Genome Atlas (TCGA) compared with normal tissues from (GTEx), using the web tool GEPIA [10], which demonstrated a trend towards increased mRNA levels which was not significant (Figure 1b); similar non-significant trends for increase in both subunits was observed in data mining across multiple cancer types (Supplementary Figure S1a). This evidence concerns the gene SLC3A2 and cancer.