The TMPro variant is a significant determinant of spontaneous metastasis, but not tumor growth. (A) Serial calipation after transplantation of LLCGFP cells into the dorsal subcutis of WT (●, n = 11) and TMPro mice (○, n = 10) revealed no genotype-dependent difference in tumor volume at any time point. Data represent means with SEM. (B) Quantitative analysis of spontaneous pulmonary metastases enumerated 14 days after primary tumor resection.