Quantification of CD44v6 and EGFR expression in head and neck squamous cell carcinomas using a single-dose radioimmunoassay.
BACKGROUND
In the growing field of tumor targeting, there is an urgent need to profile suitable molecular targets. In this study, CD44v6 and EGFR expression was quantified in samples of patients with head and neck squamous cell carcinoma (HNSCC) using a single-dose (SD) radioimmunoassay.


METHODS
The SD radioimmunoassay using 125I-chimeric monoclonal antibody (cMAb) U36 and 125I-cMAb cetuximab was first validated and then applied to quantify the expression of their target antigen molecules, CD44v6 and EGFR, in patient samples. Results were compared to immunohistochemical staining.


RESULTS
The SD assay provided sensitive quantitative values of the molecular targets studied, generally agreeing with the immunohistochemistry (IHC) results. The results indicated that expression of CD44v6 (0.2-20 nmol/mug membrane) was generally higher than that of EGFR (0.6-2.3 nmol/microg membrane) in the tumor samples analyzed, which corresponded to an average of 700,000 and 90,000 antigen molecules per cell, respectively.


CONCLUSIONS
The SD radioimmunoassay is simple, reliable, and can be performed on a small amount (50 mg) of tissue. This assay could be a useful tool in the growing field of personalized cancer therapy, and can be used as a complement to IHC. In the tumors studied, CD44v6 was generally expressed at a higher level than EGFR, which might suggest that it could be more readily targeted by MAbs.
Nestor
Marika
M
Unit of Otolaryngology and Head and Neck Surgery, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden. Marika.Nestor@bms.uu.se
Ekberg
Tomas
T
Dring
John
J
van Dongen
Guus A M S
GA
Wester
Kenneth
K
Tolmachev
Vladimir
V
Anniko
Matti
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D061067:Antibodies, Monoclonal, Humanized; D002294:Carcinoma, Squamous Cell / Q000737:chemistry* / Q000378:metabolism; D045744:Cell Line, Tumor / Q000737:chemistry; D002462:Cell Membrane / Q000737:chemistry; D000068818:Cetuximab; D066246:ErbB Receptors / Q000737:chemistry* / Q000276:immunology; D005887:Gingival Neoplasms / Q000737:chemistry / Q000378:metabolism; D006023:Glycoproteins / Q000096:biosynthesis / Q000737:chemistry* / Q000276:immunology; D006258:Head and Neck Neoplasms / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D018960:Hyaluronan Receptors / Q000096:biosynthesis / Q000737:chemistry* / Q000276:immunology; D007457:Iodine Radioisotopes / Q000032:analysis; D051379:Mice; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000276:immunology; D009368:Neoplasm Transplantation; D016612:Paraffin Embedding; D011863:Radioimmunoassay / Q000379:methods*; D014062:Tongue Neoplasms / Q000737:chemistry / Q000378:metabolism; D014609:Uvula / Q000737:chemistry
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; C112697:CD44v6 antigen; D006023:Glycoproteins; D018960:Hyaluronan Receptors; D007457:Iodine Radioisotopes; D009363:Neoplasm Proteins; C512478:EGFR protein, human; D066246:ErbB Receptors; D000068818:Cetuximab