Hypermethylation and silencing of the putative tumor suppressor Tazarotene-induced gene 1 in human cancers.

A variety of tumor suppressor genes are down-regulated by hypermethylation during carcinogenesis. Using methylated CpG amplification-representation difference analysis, we identified a DNA fragment corresponding to the Tazarotene-induced gene 1 (TIG1) promoter-associated CpG island as one of the genes hypermethylated in the leukemia cell line K562. Because TIG1 has been proposed to act as a tumor suppressor, we tested the hypothesis that cytosine methylation of the TIG1 promoter suppresses its expression and causes a loss of responsiveness to retinoic acid in some neoplastic cells. We examined TIG1 methylation and expression status in 53 human cancer cell lines and 74 primary tumors, including leukemia and head and neck, breast, colon, skin, brain, lung, and prostate cancer. Loss of TIG1 expression was strongly associated with TIG1 promoter hypermethylation (P < 0.001). There was no correlation between TIG1 promoter methylation and that of retinoid acid receptor beta2 (RARbeta2), another retinoic-induced putative tumor suppressor gene (P = 0.78). Treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine for 5 days restored TIG1 expression in all eight silenced cell lines tested. TIG1 expression was also inducible by treatment with 1 micro M all-trans-retinoic acid for 3 days except in densely methylated cell lines. Treatment of the K562 leukemia cells with demethylating agent combined with all-trans-retinoic acid induced apoptosis. These findings indicate that silencing of TIG1 promoter by hypermethylation is common in human cancers and may contribute to the loss of retinoic acid responsiveness in some neoplastic cells.

[Olfactory neuroblastoma: the Hokkaido University experience].

Olfactory neuroblastoma is such a rare malignancy that no consensus has been reached on its management. We analyzed 17 patients with olfactory neuroblastoma treated between April 1980 and March 2004--9 men and 8 women, aged 16 to 76 years old(mean: 50.4 years). Follow-up of current survivors was 1 year 8 months to 16 years 6 months (average: 7 years 9 months). Initially, 2 were treated with surgery alone, 5 with surgery and radiotherapy, and 2 with a combination of these and chemotherapy. Without surgery, radiotherapy alone was conducted in 3 and combined of radiation and chemotherapy in 5. Three of the 5 patients treated with surgery and radiotherapy survive without locoregional recurrence as do 2 with chemotherapy added. All 5 initially treated with craniofacial resection survived more than 5 years. Combined radiotherapy and chemotherapy without surgery was effective in 2. 5- and 10-year overall survival for all patients were 75.5% and 64.7%. Overall 5-year survival of 8 patients with low-grade tumors was 87.5% and of 6 with high-grade tumors 33.3%. In conclusion, combined craniofacial resection plus radiotherapy and chemotherapy seemed to improve survival. Histopathological grading is a prognostic factors.

Induction of TIG3, a putative class II tumor suppressor gene, by retinoic acid in head and neck and lung carcinoma cells and its association with suppression of the transformed phenotype.

Retinoids can regulate the proliferation and differentiation of various tumor cells. It is thought that nuclear retinoid receptors mediate these effects by regulating gene transcription. The identity of specific retinoid target genes is only beginning to be unraveled. One candidate for mediating retinoid-induced growth suppression is the novel class II tumor suppressor gene tazarotene-induced gene 3 (TIG3). We examined the constitutive and all-trans retinoic acid (ATRA)-inducible expression of TIG3 mRNA in five head and neck squamous cell carcinoma (HNSCC) and five nonsmall cell lung carcinoma (NSCLC) cell lines to determine whether it is associated with their responsiveness to ATRA. The expression patterns of retinoic acid receptor beta (RARbeta), another putative retinoid-inducible tumor suppressor gene, were also examined. The constitutive TIG3 expression was high in one HNSCC cell line and two NSCLC cell lines, and moderate to very low in the other cells. Some RARbeta-expressing cells had either low or undetectable TIG3 levels and vice versa. ATRA (1 microM; 48 h) increased TIG3 mRNA in 4/5 HNSCCs and 3/5 NSCLCs and RARbeta mRNA in some of the same cell lines, but also in cells that did not show TIG3 induction. TIG3 mRNA was induced by ATRA between 6 and 12 h in most of the responsive cells. ATRA concentrations required for TIG3 induction ranged from 1 to 500 nM depending on the cell line. The pan-RAR antagonists AGN193109 and the RARalpha antagonist Ro 41-5253 blocked TIG3 induction by ATRA. ATRA suppressed anchorage-independent colony formation in most cells that had a high or moderate constitutive or induced TIG3 expression level. In contrast, RARbeta mRNA expression pattern was not correlated with sensitivity to ATRA. These results suggest that TIG3 is regulated by ATRA via retinoid receptors in certain aerodigestive tract cancer cells, and its induction by ATRA is associated with the suppression of anchorage-independent growth.

p53 expression in concurrent chemoradiotherapy with docetaxel for head and neck squamous cell carcinoma.

BACKGROUND: The current study aimed to evaluate the significance of an immunohistochemical assessment of tumor suppressor p53 as a prognostic marker in head and neck squamous cell carcinoma (HNSCC) patients treated with docetaxel and radiotherapy. METHODS: The expression of tumor suppressor p53 and its phosphorylated form at the Ser392 residue was retrospectively evaluated by immunohistochemistry in 51 Stage T1-3N0-2M0 (except T1N0 glottis) HNSCC patients who were treated with 10mg/m(2)/week docetaxel four to six times and received concurrent chemoradiotherapy. RESULTS: Kaplan-Meier univariate analysis revealed that no difference in rates for overall and disease-free survival (DFS) between patients with p53-positive and -negative tumors (p=0.786 and p=0.924, respectively). The prognostic significance of phosphorylated p53 at the Ser392 residue was neither observed. CONCLUSIONS: An immunohistochemical assessment of the expression of p53 and its phosphorylated form might not be of clinical use in defining subgroups of patients with poor prognosis.

Prognostic significance of cyclin D1 and p16 in patients with intermediate-risk head and neck squamous cell carcinoma treated with docetaxel and concurrent radiotherapy.

BACKGROUND: The current study aimed to evaluate the significance of the cell-cycle-control proteins cyclin D1 and p16 as prognostic markers in head and neck squamous cell carcinoma (HNSCC) patients treated with docetaxel and radiotherapy. METHODS: Cyclin D1 and/or p16 protein expression was retrospectively evaluated by immunohistochemistry in 53 patients with stage T1-3N0-2M0 (except T1N0 glottis) HNSCC who were treated with 10 mg/m(2)/week docetaxel 4 to 6 times and received concurrent chemoradiotherapy. RESULTS: Kaplan-Meier univariate analysis revealed that patients with cyclin D1-positive tumors or p16-negative tumors had a worse prognosis compared with those with cyclin D1-negative tumors or p16-positive tumors (p = .0004 and p = .025, respectively). The prognostic significance of cyclin D1 expression, not p16 expression, was confirmed using a proportional hazard regression model. CONCLUSIONS: An assessment of cyclin D1 and p16 levels might be of clinical use in defining subgroups of patients with poor prognosis.

"Watch-and-see" policy for the clinically positive neck in head and neck cancer treated with chemoradiotherapy.

BACKGROUND: Chemoradiotherapy (CRT) is becoming more widely used for head and neck cancer. However, there are conflicting theories regarding the best management options for patients with advanced nodal disease. METHODS: From 1990 to 1999, we treated 96 patients with N1-N2 neck disease by concomitant CRT for organ preservation, using weekly carboplatin or a low daily dose of cisplatin, followed by a "watch-and-see" policy for the neck. In the present study, we retrospectively analyzed the treatment outcome in 63 of these patients who received definitive CRT for primary and neck diseases and were monitored for neck disease for more than 2 years. RESULTS: In 12 of the 22 (55%) N1 patients, CRT successfully controlled the neck disease. CRT was successful in 18 of the 41 (44%) patients with N2 disease. In 6 (60%) of 10 patients with residual or recurrent N1 disease, salvage surgery was successful. Of the 23 patients with residual or recurrent N2 disease, salvage surgery was successful in 8 patients (35%). The group of patients who showed a clinical complete response (CCR) to CRT had an overall survival rate of 62.4% (33 patients), whereas for those with a less than complete response (

Differentially expressed genes associated with CIS-diamminedichloroplatinum (II) resistance in head and neck cancer using differential display and CDNA microarray.

BACKGROUND: The mechanism by which cancer cells become resistant to cis-Diamminedichloroplatinum (II) (cDDP) is not completely understood. To investigate the molecular markers involved in the cDDP resistance, we compared the gene expression profiles between a head and neck squamous cell carcinoma (HNSCC) line sensitive to cDDP and its cDDP-resistant variant. METHODS: Both a fluorescent differential display and a cDNA microarray analysis were applied to distinguish the gene profiles between KB, a human HNSCC line, and its cDDP-resistant variant (KB/cDDP). These results were confirmed by Northern blot analysis. RESULTS: One up-regulated gene, glycoprotein hormone alpha-subunit, and two down-regulated genes coding membrane proteins, human folate receptor and tumor-associated antigen L6, were identified in KB/cDDP cells. CONCLUSIONS: Our findings suggest that development of the cDDP-resistant phenotype is accompanied by alternations of gene expression including a glycoprotein hormone and membrane proteins. These gene products could be new molecular markers for resistance to cDDP.