A. K. El-Naggar

Carcinoma of the thyroid gland, the most frequently diagnosed endocrine malignancy, is often associated with early regional metastases. With the exception of papillary carcinoma, distinguishing benign from malignant thyroid neoplasms in the absence of metastatic disease is difficult. Recently, the vertebrate lectins galectin-1 and galectin-3 have been implicated in the regulation of cellular growth, differentiation, and malignant transformation of a variety of tissues. To determine whether these galectins have a role in thyroid neoplasia, we analyzed 32 specimens from thyroid malignancies (16 papillary, 7 follicular, 8 medullary carcinomas, and 1 metastasis to lymph node), 10 benign thyroid adenomas, 1 nodular goiter, and 33 specimens from adjacent normal thyroid tissue for the expression of galectin-1 and galectin-3 with immunohistochemical and immunoblotting techniques utilizing anti-galectin antibodies. All thyroid malignancies of epithelial origin (ie, papillary and follicular carcinomas) and a metastatic lymph node from a papillary carcinoma expressed high levels of both galectin-1 and galectin-3. The medullary thyroid carcinomas, which are of parafollicular C cell origin, showed a weaker and variable expression of these galectins. In contrast, neither benign thyroid adenomas nor adjacent normal thyroid tissue expressed galectin-1 or galectin-3. These results suggest that galectin-1 and galectin-3 may be associated with malignant transformation of thyroid epithelium and may potentially serve as markers for distinguishing benign thyroid adenomas from differentiated thyroid carcinomas.

5500 Background: The concurrent use of cisplatin (CDDP) or cetuximab (CET) with radiation (RT) has been shown to improve survival of patients with stage III-IV HNC. Since CET enhances the response of metastatic HNC to platinum-containing regimens and survival, the RTOG launched a phase III trial to test the hypothesis that adding CET to the RT-CDDP platform for frontline therapy of stage III-IV HNC improves progression free survival. Methods: Patients with stage III-IV carcinoma of the oropharynx, larynx, and hypopharynx, having Zubrod performance of 0-1, and meeting predefined blood chemistry criteria were enrolled after providing consent. The experimental regimen (Arm A) consisted of a loading dose and 6-7 weekly doses of CET given in conjunction with the control arm (B) of 70-72 Gy (6 weeks) + 2 cycles of CDDP (q3 weeks). Results: From 11/’05 to 3/’09, 940 patients were enrolled. Of the 895 evaluable patients, 447 randomized to Arm A and 448 to Arm B. Over 90% of patients received 2 CDDP cycles in both arms and 74% of cases received the loading plus 6 or more doses of CET in Arm A. The median follow-up was 2.4 years for surviving patients. There were no significant differences in progression-free survival (HR [A/B]: 1.05, 0.84-1.29; P=0.66; 2-Y rates: 63% vs. 64%), the primary endpoint, or in overall survival (HR: 0.87, 0.66-1.15; P=0.17; 2-Y rates: 83% vs. 80%), death within 30 days of therapy (2.0% vs. 1.8%, P=0.81), and total grade 3-5 adverse events (92% vs. 90%, P=0.30). Arm A had higher rates of grade 3-4 mucositis (45% vs. 35%, P=0.003) and skin reactions (40% vs. 17%, P<0.0001) but grade 3-4 dysphagia rates were not significantly different (62% vs. 66%, P=0.27). Conclusions: The addition of cetuximab to the radiation-cisplatin platform did not improve progression-free or overall survival. The triplet regimen was associated with higher rates of mucositis and CET-induced skin reactions but no unexpected toxicity was observed. Whether tumor human papillomavirus status would affect the relative efficacy of the triplet regimen and the overall outcome of this trial is being addressed. Funding: NCI U10CA21661, U10CA37422, and Bristol-Myers Squibb.

Cancer gene therapy strategies for inducing apoptosis in solid tumors may allow contemporary medicine to reassess its management of these cancers. We demonstrated previously that overexpression of the wild-type p53 gene in squamous cell carcinoma of the head and neck cell lines via adenovirus-mediated gene transfer suppressed growth both in vitro and in vivo. Here, we characterize the mechanism of the growth suppression by the exogenous p53 gene as a consequence of programmed cell death (apoptosis). One of the cell lines used in this study, Tu-138, harbors a mutated p53 gene, whereas the other cell line, MDA 686LN, possesses a wild-type p53 gene. DNA fragmentation was detected by electrophoresis in both cell lines after infection with the wild-type p53 adenovirus, Ad5CMV-p53. With the use of the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling method, 4.4% of the remaining viable Tu-138 cell population was identified as apoptotic as early as 15 h after inoculation with Ad5CMV-p53. The percentage of apoptotic cells increased to 31% at 22 h. In contrast, only 10% of the viable MDA 686LN cells (wt-p53) had undergone apoptosis 30 h after Ad5CMV-p53 infection, although the percentage of apoptotic cells rapidly increased to 60% at 48 h after infection. For in vivo analysis of apoptosis, nude mice in which squamous cell carcinoma of the head and neck cell lines had been implanted s.c. had exogenous wt-p53 transiently introduced to the tumor cells via Ad5CMV-p53 2 days later. In situ end labeling clearly illustrated apoptosis in the tumor cells. These results suggest that wt-p53 plays an important role in the induction of apoptosis in human head and neck cancer cell lines and that selective induction of apoptosis in cancer cells can be further explored as a strategy for cancer gene therapy.

BACKGROUND: The goal of chemoprevention is to reduce the risk of cancer development by reversing or blocking the tumorigenic process through the use of pharmacologic or natural agents. To determine the potential role of genetic alterations in assessing cancer risk and in evaluating the efficacy of chemopreventive agents, we studied 22 patients with advanced premalignant lesions of the head and neck who were part of a prospective cancer prevention trial that is investigating a regimen of 13-cis-retinoic acid, interferon alfa, and alpha-tocopherol administered for 12 months or until disease progression. METHODS: We used polymerase chain reaction analysis of microsatellite DNA sequences in cells from precancerous lesions to determine the frequencies of genetic alterations--namely, loss of heterozygosity (LOH) and microsatellite instability--at chromosomal loci that are commonly deleted in head and neck cancer. RESULTS: Prior to treatment, 17 (81%) of 21, eight (44%) of 18, and eight (42%) of 19 patients who were informative (i.e., heterozygous) at chromosomes 9p21, 3p14, and 17p13, respectively, exhibited LOH in at least one of their lesion biopsy specimens. Among nine patients who exhibited LOH at chromosome 9p21 in pretreatment biopsy specimens and who had completed at least 5 months of therapy, the genetic loss persisted in eight--including three of the four patients who exhibited complete histologic responses (i.e., no evidence of dysplasia in their biopsy specimens). IMPLICATION: Our data suggest that clinical and histologic assessments of the response to chemopreventive agents may be insufficient to determine their efficacy and that critical genetic alterations could be used as independent biomarkers to augment the ability to evaluate the efficacy of such agents.

Multiple and distinct p53 mutations were detected by DNA sequence analysis in tumor and adjacent nonmalignant skin samples from eight patients with nonmelanoma skin cancer of the head and neck, providing unambiguous evidence for field cancerization. The mutations consisted of C-->T transitions at dipyrimidine sequences (30% of all single base substitutions), T-->C transitions (47%), and G-->T transversions (12%), suggesting that other carcinogens may act along with UV radiation in the development of nonmelanoma skin cancer. Patient interviews revealed that, in addition to substantial exposure to solar UV radiation, most had a history of smoking and were exposed to carcinogens from industrial or agricultural sources. These data show that extensive molecular epidemiological investigations are necessary to elucidate risk factors associated with the disease in localities where patients often report substantial exposure to environmental carcinogens.