Relative expression of members of the Sdc4:RTK:ITG complex on nontumorigenic and neoplastic epithelial cells. Cell surface of expression of Sdc4 (mAb 8G3, red), Sdc2 (mAb 305515, orange), α3β1 (mAb P1B5, blue), α6β4 (mAb 3E1, green), EGFR (mAb EGFR.1, black), and RON (FAB6647F, purple) were analyzed by flow cytometry compared to nonspecific IgG (gray profile) on A, HNSCC (UM-SCC47, UM-SCC1) and TNBC (MDA-MB-231) cells or B, nontransformed HaCaT, HTE, or NOK epithelial cells. EGFR, epidermal growth factor receptor; HNSCC, head and neck squamous cell carcinoma; HTE, human tonsillar epithelial cell; NOK, normal oral keratinocyte; RON, recepteur d’origine nantais; Sdc2, syndecan-2; Sdc4, syndecan-4; TNBC, triple-negative breast cancer.