Transforming growth factor beta receptors in verrucous and squamous cell carcinoma.

OBJECTIVES

To study the intracellular location of transforming growth factor beta type II receptors (TbetaR-II) in verrucous carcinoma (VC) and squamous cell carcinoma (SqCC), and to evaluate their role in the biological behavior of both neoplasias.

DESIGN

Ten VC and 10 well-differentiated SqCC specimens were analyzed by immunohistochemistry and in situ hybridization for the expression and intracellular location of TbetaR-II. Receptor expression was evaluated in areas of invasion and in areas of transformation of VC into SqCC. TbetaR-II expression was compared with expression of the type I receptor (TbetaR-I).

SUBJECTS

Formalin-fixed, paraffin-embedded tissue sections from VCs and well-differentiated SqCCs, operated on at the H. L. Moffitt Cancer Center and Research Institute from May 1987 to January 1998, were selected for the study.

INTERVENTIONS

None.

RESULTS

While in all VCs TbetaR-II was found to be located along the membrane of the neoplastic keratinocytes, TbetaR-II expression in SqCC was observed predominantly in a cytoplasmic location. This cytoplasmic location of TbetaR-II was also seen in areas of transition from VC to SqCC. Expression of TbetaR-I was found in a cytoplasmic location in both tumor types.

CONCLUSIONS

The membranous location of TbetaR-II in VC exposes the receptor to the growth inhibitory control of TGF-beta and may explain why VC tumors are less aggressive clinically. The marked reduction of membranous TbetaR-II and their predominant cytoplasmic location diminishes TGF-beta growth inhibition and may contribute to the transformation of VC into the more aggressive SqCC.