Weinberg and Spranger Lab researchers are studying the biology behind two of cancer's most deadly evolutions—metastasis and resistance to treatment. Previous work showed that quasi-mesenchymal cells cross-protect their epithelial neighbors in the same tumor and shield it from immune attack, keeping out cancer-destroying immune cells. In new work supported by the Ludwig Center for Molecular Oncology at MIT and appearing in Cancer Discovery, researchers identified six quasi-mesenchymal molecules that help carry out this defense. Of the six, the enzyme CD73 proved most effective in making breast carcinoma cells more vulnerable to immunotherapy and reducing the severity of metastasis.