PTK2 and ductal breast carcinoma in situ: In a study on ductal carcinoma in situ (DCIS), Williams et al. showed that CSC-enriched populations were more radio-resistant due to higher levels of FAK activity, and inhibition of FAK both in vitro and in vivo decreased the self-renewal capacity of these cells, accompanied by a reduction in Wnt3a and β-catenin levels.