Head and neck cancer: The pursuit of molecular diagnostic markers

Molecular Alterations in Oral Carcinogenesis: Significant Risk Predictors in Malignant Transformation and Tumor Progression

In this study an attempt was made to establish the significance of a battery of molecular alterations and thereby identify risk predictors in oral carcinogenesis. For this purpose, EGFR, Stat3, H-ras, c-myc, p53, cyclin D1, p16, Rb, Ki-67 and Bcl-2 were localized immunohistochemically in normal mucosa (n=12), hyperplasia (n=35), dysplasia (n=25), early stage carcinoma (n=65) and advanced stage carcinoma (n=70). Deregulation occurred at an early stage and the number of alterations increased with disease progression. Using multivariate logistic regression analysis, the significant risk predictor for hyperplasia from normal mucosa was Ki-67 (OR=5.75, p=0.021); the significant risk predictors for dysplasia from hyperplasia were EGFR (OR=12.96, p=0.002), Stat3 (OR=17.16, p=0.0001), p16 (OR=5.50, p=0.039) and c-myc (OR=5.99, p=0.052); the significant risk predictors for early stage carcinoma from dysplasia were p53 (OR=6.63, p=0.0001) and Rb (OR=3.81, p=0.056); and the significant risk predictors for further progression were EGFR (OR=5.50, p=0.0001), Stat3 (OR=4.49, p=0.0001), H-ras (OR=4.05, p=0.001) and c-myc (OR=2.99, p=0.015). Cyclin D1 holds a key position linking upstream signaling pathways to cell cycle regulation. Gene products of the mitogenic signaling pathway play an equally significant role as cell cycle regulatory proteins in the hyperplasia-dysplasia-early-advanced-carcinoma sequence and together may provide a reference panel of markers for use in defining premalignant lesions and predicting the risk of malignant transformation and tumor progression.

Gene expression signatures and molecular markers associated with clinical outcome in locally advanced head and neck carcinoma

The purpose of this study was to identify molecular markers associated with tumor recurrence and survival in patients with locally advanced head and neck squamous cell carcinoma (HNSCC). We studied the expression profile of 63 pre-treatment tumor biopsies obtained from locally advanced HNSCCs treated with standard treatments. Cluster analysis identified three tumor subtypes associated with significant differences in local recurrence-free survival (LRFS) (P<0.001), progression free-survival (PFS) (P<0.009) and overall survival (OS) (P<0.004). Tumor subtype 1, associated with short LRFS, PFS and OS, showed features of epithelial-mesenchymal transition and undifferentiation. It also overexpressed genes involved in cell adhesion, NF-κB and integrin signalling. Tumor subtype 3, associated with longer LRFS, PFS and OS, showed a high degree of differentiation and overexpressed genes located in chromosomal regions 19q13 and 1q21. Tumor subtype 2, which had an intermediate clinical outcome between subtype 1 and subtype 3, overexpressed genes involved in branching morphogenesis. Finally, we validated the association between gene cluster classification and patient survival using Gene Set Enrichment Analysis and two HNSCC data sets obtained from two independent patient cohorts. In conclusion, we generated a gene prognostic signature associated with survival in locally advanced patients using the expression profile of the pre-treatment tumor biopsy. Independent prospective studies would be necessary to assess if the proposed survival signature could help to guide clinical management of HNSCC.

Expression of a novel marker, Ubc9, in squamous cell carcinoma of the head and neck

BACKGROUND

Ubiquitin-conjugating enzyme (Ubc9) is a novel enzyme involved in posttranslational modification of cellular proteins. The objective of this study was to determine the expression of Ubc9 in squamous cell carcinoma of the head and neck (SCCHN).

METHODS

SCCHN specimens were stained with anti-Ubc9 antibodies, scored using a semiquantitative method, and statistically analyzed.

RESULTS

Forty-six tumors were stained, 26 of which included adjacent mucosa. Ubc9 was significantly upregulated in the malignant and peritumoral tissues compared with mucosa from normal individuals. In peritumoral tissues, Ubc9 expression was detected in the basal and suprabasal epithelial layers. No Ubc9 was detected in epithelial cells in normal mucosa. These differences in Ubc9 expression were statistically significant (p < .0001). Tumor Ubc9 expression significantly correlated with clinical and pathologic stage.

CONCLUSIONS

Ubc9 is significantly overexpressed in the primary SCCHN tumors and peritumoral mucosa compared with normal epithelial cells. These findings suggest that Ubc9 may play an important role in tumorigenesis and tumor progression of SCCHN.

Squamous metaplasia and chronic rhinosinusitis: a clinicopathological study

BACKGROUND

The significance of squamous metaplasia (SM) in chronic rhinosinusitis (CRS) is unknown. The objectives of this study were to determine the prevalence of SM in histopathological specimens from patients with CRS and to correlate these histological findings with clinical features.

METHODS

We reviewed the clinical records and pathological slides from 87 consecutive patients who underwent endoscopic sinus surgery for CRS. Demographic and clinical data, preoperative Chronic Sinusitis Survey (CSS) scores, and sinus CT stage were evaluated. Pathological slides were graded by a pathologist to characterize the degree of inflammation and SM, when present. CRS patients with and without SM were compared using student's t-test and chi2 test.

RESULTS

Evaluation of the pathology slides revealed that 18.4% of specimens had SM present, whereas only 2.2% of pathology reports noted this. Histological grading of chronic inflammation showed significantly greater severity in specimens with SM (n = 16) when compared with the cohort without SM (n = 75; 100.0% versus 77.5%, respectively; p = 0.016). There was no difference in preoperative CT stage or the presence of hyperostosis on imaging, CSS scores, duration of CRS symptoms, or other clinical features between those with SM and those without SM (p > 0.05). Immunodeficiency was the only comorbidity more prevalent in the metaplastic group (12.5% versus 0%, respectively; p = 0.003).

CONCLUSION

SM is present in approximately 18% of routine CRS specimens. It has a positive correlation with the severity of inflammation noted histologically in CRS but does not correlate with disease severity or chronicity, clinically.

Ku70 predicts response and primary tumor recurrence after therapy in locally advanced head and neck cancer

5-Fluorouracil and cisplatin-based induction chemotherapy (IC) is commonly used to treat locally advanced head and neck squamous cell carcinoma (HNSCC). The role of nonhomologous end joining (NHEJ) genes (Ku70, Ku80 and DNA-PKcs) in double-strand break (DSB) repair, genomic instability and apoptosis suggest a possible impact on tumor response to radiotherapy, 5-fluorouracil or cisplatin, as these agents are direct or indirect inductors of DSBs. We evaluated the relationship between Ku80, Ku70 or DNA PKcs mRNA expression in pretreatment tumor biopsies, and tumor response to IC or local recurrence, in 50 patients with HNSCC. Additionally, in an independent cohort of 75 patients with HNSCC, we evaluated the relationship between tumor Ku70 protein expression and the same clinical outcomes or patient survival. Tumors in the responder group had significantly higher mRNA levels for Ku70, Ku80 and DNA-PKcs than those in the nonresponder group. Ku70 mRNA was the marker most significantly associated with response to IC. Moreover, high tumor Ku70 mRNA expression was associated with significantly longer local recurrence-free survival (LRFS). Ku70 protein expression was also significantly related to response, and patients with higher percentage of tumor cells expressing Ku70 had longer LRFS. In addition, the percentage of Ku70 positive cells, tumor localization and node involvement were significantly associated with overall survival of patient. Therefore, Ku70 expression is a candidate predictive marker that could distinguish patients who are likely to benefit from chemoradiotherapy or radiotherapy after the induction chemotherapy treatment, suggesting a contribution of the NHEJ system in HNSCC clinical outcome.

Protein microarrays for the detection of biomarkers in head and neck squamous cell carcinomas

Protein microarrays are of increasing importance for high-throughput screening of fresh tissues. In our study, protein microarrays were generated by printing antibodies onto membranes to characterize protein profiles expressed by head and neck squamous cell carcinomas (HNSCCs). Cellular proteomes of 30 matched normal squamous epithelial cells and carcinoma specimens were analyzed after tissue microdissection using microarrays composed of 83 different antibodies. As controls, Western blot analysis and tissue microarrays (TMAs) containing 98 HNSCC specimens were used. Of the 83 proteins examined, 14 showed differential expression between HNSCCs and normal epithelium. The protein microarray approach revealed an upregulation of 8 proteins and a downregulation of 6 proteins. Bag-1, Cox-2, Hsp-70, Stat3, pescadillo, MMP-7 (matrilysin), IGF-2, and cyclin D1 were identified to be significantly upregulated, whereas suppressor of cytokine signaling 1, thrombospondin, TGF-beta1, Jun, Fos, and Fra-2 were downregulated. The differential expression of these proteins was confirmed using Western blot and TMA. Upon correlation of differentially regulated proteins with the clinicopathologic data of our patients, MMP-7 (matrilysin) was found to be associated with survival in univariate, but not multivariate, analysis. These data indicate that our protein arrays provide protein information in a systematic, reproducible, and also high-throughput fashion.

Head and neck squamous cell carcinoma transcriptome analysis by comprehensive validated differential display

Head and neck squamous cell carcinoma (HNSCC) is common worldwide and is associated with a poor rate of survival. Identification of new markers and therapeutic targets, and understanding the complex transformation process, will require a comprehensive description of genome expression, that can only be achieved by combining different methodologies. We report here the HNSCC transcriptome that was determined by exhaustive differential display (DD) analysis coupled with validation by different methods on the same patient samples. The resulting 820 nonredundant sequences were analysed by high throughput bioinformatics analysis. Human proteins were identified for 73% (596) of the DD sequences. A large proportion (>50%) of the remaining unassigned sequences match ESTs (expressed sequence tags) from human tumours. For the functionally annotated proteins, there is significant enrichment for relevant biological processes, including cell motility, protein biosynthesis, stress and immune responses, cell death, cell cycle, cell proliferation and/or maintenance and transport. Three of the novel proteins (TMEM16A, PHLDB2 and ARHGAP21) were analysed further to show that they have the potential to be developed as therapeutic targets.