COL3A1 and neoplasm: Furthermore, significant higher expression of COL1A1 in dLN (vs BME p=0.0075, vs dLU p=0.013) and COL3A1 in BME (vs dLU p=0.007) indicates that the reciprocal production of ECM proteins by tumor cells is also affected by the ECM of the metastatic organ (Figure 5E).