Potential biomarkers for head and neck squamous cell carcinoma.
OBJECTIVE
The purpose of the study was twofold: 1) to search for potential biomarkers that were overexpressed in cell lines that could represent both a clinical premalignant (immortalized) and a malignant state, and 2) to attempt to correlate metallothionein gene expression with clinical outcome in laryngeal carcinoma.


METHODS
A series of in vitro experiments were used to unearth differentially expressed genes among normal, immortalized and tumorigenic cell lines. Secondarily, a retrospective analysis was undertaken.


METHODS
Differential display analysis was conducted to identify differentially expressed genes between human papillomavirus-infected immortalized HOK16B and benzo[ ]pyrene-derived tumorigenic cell line, HOK16B-BaP-T. The cell-specific expressions were examined by Northern blot analysis and compared with other known immortalized and cancer cell lines. Immunohistochemical staining was also conducted to localize metallothionein (MT I/II) protein expression among the different cell lines studied. A retrospective analysis of laryngeal specimens from archival tissues of 29 cancer patients who underwent primary surgical resection was also undertaken after immunohistochemical staining.


RESULTS
Twenty-one differentially expressed complementary cDNA clones, both novel and known, were identified using the differential display analysis. Northern blot analysis confirmed that clone 6 hybridized to a 1.6-kb RNA in HOK16B-Bap-T cell line. Clone 4 showed decreased expression in immortalized and cancer cell compared with NHOK. MT I/II transcript was observed in HOK16B, which was further elevated in HOK16B-Bap-T. Retrospective analysis showed that high immunoreactivity to MT I/II in surgically resected laryngeal cancer specimen correlated with increased frequency of recurrence within 2 years of surgery.


CONCLUSIONS
These findings suggest that clone 4 may potentially function as a tumor suppressor gene, which may be significant in tumor progression and invasion. Clone 6 may participate in viral-mediated oncogenic transformation of normal cells. Clone 6 may also have potential as a tumor maker differentiating normal from malignant tissue, as in the determination of surgical resection margins. MT I/II gene product may serve as a prognostic biomarker for laryngeal squamous cell carcinoma. The differentially expressed genes and gene products may serve as sensitive biomarkers for improved early detection, diagnosis, and prognosis of head and neck squamous cell carcinoma.
Brown
Jimmy J
JJ
Department of Otolaryngology-Head and Neck Surgery, Charles R. Drew University of Medicine and Science, 1731 East 20th Street, Los Angeles, CA 90059, USA. jimbrown@cdrewu.edu
Xu
Helen
H
Nishitani
Junko
J
Mohammed
Hezla
H
Osborne
Ryan
R
Teklehaimanot
Senait
S
Gill
Gus
G
Liu
Xuan
X
D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins; D015152:Blotting, Northern; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology; D018929:Cell Culture Techniques; D002999:Clone Cells / Q000473:pathology; D018076:DNA, Complementary / Q000235:genetics; D029968:Escherichia coli Proteins; D005260:Female; D015870:Gene Expression; D016147:Genes, Tumor Suppressor / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D007822:Laryngeal Neoplasms / Q000235:genetics* / Q000473:pathology; D008297:Male; D008668:Metallothionein / Q000235:genetics; D008875:Middle Aged; D009367:Neoplasm Staging; D012313:RNA / Q000235:genetics; D012189:Retrospective Studies
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D018076:DNA, Complementary; D029968:Escherichia coli Proteins; C087025:Hok protein, E coli; D012313:RNA; D008668:Metallothionein