Fig. 1

mCol1a1 does not alter the rate of tumor growth, but increases circulating tumor cells. a-b Tumor growth of tumor cell line (TC)2 (a) and TC4 (b) tumors until collection of the largest tumors began. Tumor volume was measured biweekly. Mean ± SEM TC2 animals: wild-type (WT) n = 7, mCol1a1 n = 6. TC4 animals: WT n = 7, mCol1a1 n = 8. Time significantly influenced tumor volume in both TC2 (a) and TC4 (b) tumors (p < 0.0001, two-way repeated measures ANOVA), but genotype did not. c-d Circulating tumor cells (CTCs) in peripheral blood of animals bearing TC2 (c) or TC4 (d) tumors. Peripheral blood was collected weekly and analyzed for green fluorescent protein positive (GFP+) CTCs as described in “Methods”. Mean ± SEM TC2 recipients: WT n = 7, mCol1a1 n =6. TC4 recipients: WT n = 7, mCol1a1 n =8. Genotype significantly altered levels of CTCs (TC2, p < 0.0050; TC4, p < 0.0320; repeated measure two-way ANOVA, taking into account values across days in the same animals). Levels of CTCs peaked when tumors were relatively small, regardless of genotype (TC2, day 17 is significantly different from all other days except day 38, *p < 0.05; TC4, day 31 is significantly higher than day 17 and day 38, *p < 0.05)