ABSTRACT
Altered expression of growth factors and growth factor receptors is frequently described in human tumors and human tumor cell lines. This further supports the hypothesis that oncogenesis is due to the subversion of mitogen-responsive pathways. The aim of this study was to investigate the expression of epidermal growth factor receptor (EGFR) and transforming growth factor alpha (TGF alpha) in 13 larynx carcinomas and 2 carcinomas of the oral cavity. We found receptor overexpression in 7 out of 15 tumors at mRNA and/or protein level but low expression in the majority of the normal adjacent tissues. TGF alpha was expressed only in 1 case, but no tyrosine kinase activity of the receptor was detected by antiphosphotyrosine antibody.
Subject(s)
Carcinoma, Squamous Cell/genetics , ErbB Receptors/genetics , Laryngeal Neoplasms/genetics , Mouth Neoplasms/genetics , Transforming Growth Factor alpha/genetics , Aged , Aged, 80 and over , Biomarkers, Tumor/analysis , Carcinoma, Squamous Cell/chemistry , Electrophoresis, Polyacrylamide Gel , Humans , Immunoblotting , Laryngeal Neoplasms/chemistry , Middle Aged , Mouth Neoplasms/chemistry , RNA, Messenger/analysis , RNA, Neoplasm/analysisABSTRACT
Over the past few years, beta-carotene has progressively gained ground as a drug chosen in the treatment of oral leukoplakias, thus making it possible to reduce the use of 13-cis-retinoic acid, which was shown by many studies to be highly toxic while beta-carotene has proved to have no significant side effects and hence to be much more suitable in oral premalignancy. In 1989, a phase II study of patients showing oral leukoplakias and treated with beta-carotene (90 mg/day) was begun. A total of 23 patients (aged between 17 and 85) were included in the study and 18 (8 male and 10 female) were evaluated. Eight patients (44.4%) had objective responses (6 complete, 2 partial). Four CR and a PR appeared unexpectedly within 2-7 months after the end of the therapy. The lesions were macroscopically and histologically examined at entry; in the evaluated patients, two types of alterations were found: atypical hyperplasia (16 patients) and dysplasia (2 patients). No signs of significant toxicity were detected; only in 1 patient treatment had to be interrupted for 1 week. The results of this study show the fair efficacy of beta-carotene against oral leukoplakias, but further confirmations through controlled clinical studies are needed.
