Likewise, the deconvolved expression profiles for X3 and X13 included KRT1, a keratin gene specifically expressed in mammary myoepithelial cells33, and PRSS23, a serine protease associated with proliferation of breast cancer cells34, respectively, consistent with the non-malignant and DCIS annotations (Supplementary Fig. S17). Here, PRSS23 is linked to ductal breast carcinoma in situ.