KRT14 and neoplasm: Although both tumor size and lung metastasis were greater for the K14.GFP+ group, correlation coefficient analysis of matched pairs of primary tumors and lung metastases from all groups showed that lung metastasis did not correlate with primary tumor mass (Fig 2E), demonstrating that the increase in lung metastasis is not simply due to the increase in mass of the primary tumor in mice injected with K14.GFP+ cells.