STK11 and breast cancer: Clinical data shows LKB1 loss in more invasive cancers and in vitro data suggests association between loss of LKB1 and acquisition of pro-migratory and pro-invasive properties [46-48], However, despite these pro-growth and pro-metastatic phenotypes, we consistently observed a decrease in the ability of LKB1-deficient breast cancer cells to grow as metastases in the lung (Figure 3), suggesting that LKB1 is required for efficient tumor cell growth in a metastatic setting.