SOST and breast cancer: In addition, IHC analysis of 69 pairs of primary breast cancer foci and corresponding metastatic lesions in multiple organs revealed that SOST expression increased in both primary foci and bone metastasis tissues, compared to normal breast tissue and breast cancer tissue without bone metastasis, while SOST expression was lower in the liver and lung metastatic lesions (Fig. 1C-D), supporting the relevance of SOST to breast cancer bone metastasis.