RADIATION TREATMENT DECREASES TRANSFORMING GROWTH-FACTOR-ALPHA EXPRESSION IN SQUAMOUS CARCINOMA OF THE TONGUE

Ionizing radiation (XRT) is often used to treat squamous cell carcinom a of the tongue (SCCT) but little is known of its genetic effects on s urviving cancer cells. The effect of XRT on p53, epidermal growth fact or receptor (EGFR), and transforming growth factor alpha (TGF alpha) t umor marker expression was evaluated using immunohistochemical analysi s in 79 patients with SCCT. Sixty-six patients received no radiation, while 13 received XRT before surgery. Radiation did not influence EGFR or p53 expression. TGF alpha expression, however, was significantly d ecreased in radiated tumors (15% versus 43%, P = 0.04). These data sug gest that XRT either decreases the expression of TGF alpha in SCCT (su ggesting a genetic alteration in surviving cancer cells), or does not kill cancer cells with decreased TGF alpha expression. In the latter c ase, diminished TGF alpha expression may serve as a marker of radiores istance.