Metastasis inside-out: dissemination of cancer cell clusters with inverted polarity.

Zajac et al (2018) utilize patient tissue to discover a novel cellular mechanism for metastasis in colorectal cancer. They isolated cancer cell clusters from patient peritoneal fluid and demonstrated that these clusters invaded collectively into collagen gels, patient‐derived tissues, and through the peritoneum of mice. During invasion the clusters retained an inverted epithelial architecture, functioning as multicellular metastatic seeds with inverted polarity.