Since > 90% of XDGs were down-XDGs in PDX tumor and enriched for stroma-related pathways, the hypothesis that XDGs are predominately due to the loss of human stroma in PDX tissues was further examined using a public OC expression dataset derived from tumors in which the RNAseq was separately performed on epithelial carcinoma or the surrounding stromal components. The gene discussed is BGLAP; the disease is carcinoma.