Hypoxia-related mechanisms could potentially modulate tumor development in our setup as supported by a trend towards the increased expression of Sox2, Tert, Pou5f1 and Cxcr4 in AOM/DSS tumors from Stat3CCol1a2 mice, but we did not detect a direct regulation of HIF by STAT3 in purified COL1+ fibroblasts in an oxygen-independent manner. This evidence concerns the gene CXCR4 and infectious otitis media.