Aberrant methylation inactivates somatostatin and somatostatin receptor type 1 in head and neck squamous cell carcinoma.
OBJECTIVE
The aim of this study was to define somatostatin (SST) and somatostatin receptor type 1 (SSTR1) methylation profiles for head and neck squamous cell carcinoma (HNSCC) tumors at diagnosis and follow up and to evaluate their prognostic significance and value as a biomarker.


METHODS
Gene expression was measured by quantitative RT-PCR. Promoter methylation status was determined by quantitative methylation-specific PCR (Q-MSP) in HNSCC.


RESULTS
Methylation was associated with transcription inhibition. SST methylation in 81% of HNSCC tumor specimens significantly correlated with tumor size (P = 0.043), stage (P = 0.008), galanin receptor type 2 (GALR2) methylation (P = 0.041), and tachykinin-1 (TAC1) (P = 0.040). SSTR1 hypermethylation in 64% of cases was correlated with tumor size (P = 0.037), stage (P = 0.037), SST methylation (P < 0.001), and expression of galanin (P = 0.03), GALR2 (P = 0.014), TAC1 (P = 0.023), and tachykinin receptor type 1 (TACR1) (P = 0.003). SST and SSTR1 promoter hypermethylation showed highly discriminating receiver operator characteristic curve profiles, which clearly distinguished HNSCC from adjacent normal mucosal tissues. Concurrent hypermethylation of galanin and SSTR1 promoters correlated with reduced disease-free survival (log-rank test, P = 0.0001). Among patients with oral cavity and oropharynx cancer, methylation of both SST and SSTR1 promoters correlated with reduced disease-free survival (log-rank test, P = 0.028). In multivariate logistic-regression analysis, concomitant methylation of galanin and SSTR1 was associated with an odds ratio for recurrence of 12.53 (95% CI, 2.62 to 59.8; P = 0.002).


CONCLUSIONS
CpG hypermethylation is a likely mechanism of SST and SSTR1 gene inactivation, supporting the hypothesis that SST and SSTR1 play a role in the tumorigenesis of HNSCC and that this hypermethylation may serve as an important biomarker.
Department of Otolaryngology/Head and Neck Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan.
Kiyoshi
K
Misawa
Department of Otolaryngology/Head and Neck Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan.
Yuki
Y
Misawa
Department of Otolaryngology/Head and Neck Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan.
Haruki
H
Kondo
Department of Otolaryngology/Head and Neck Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan.
Daiki
D
Mochizuki
Department of Otolaryngology/Head and Neck Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan.
Atsushi
A
Imai
Department of Head and Neck, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo, Japan.
Hirofumi
H
Fukushima
Department of Otorhinolaryngology, Head and Neck Surgery, Graduate school of Medicine, University of the Ryukyus, Okinawa, Japan.
Takayuki
T
Uehara
Department of Otolaryngology/Head and Neck Surgery, Jichi Medical University, Shimotsuke, Japan.
Takeharu
T
Kanazawa
Department of Otolaryngology/Head and Neck Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan.
Hiroyuki
H
Mineta
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D018899:CpG Islands; D019175:DNA Methylation; D005260:Female; D019004:Galanin / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006258:Head and Neck Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D009367:Neoplasm Staging; D016017:Odds Ratio; D009959:Oropharyngeal Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D011401:Promoter Regions, Genetic; D044092:Receptor, Galanin, Type 2 / Q000235:genetics / Q000378:metabolism; D017481:Receptors, Somatostatin / Q000235:genetics* / Q000378:metabolism; D012189:Retrospective Studies; D012307:Risk Factors; D013004:Somatostatin / Q000235:genetics* / Q000378:metabolism; D000077195:Squamous Cell Carcinoma of Head and Neck; D016019:Survival Analysis; D015320:Tachykinins / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D014408:Biomarkers, Tumor; D044092:Receptor, Galanin, Type 2; D017481:Receptors, Somatostatin; D015320:Tachykinins; C101130:somatostatin receptor type 1; D013004:Somatostatin; D019004:Galanin