Receptor tyrosine kinase profiles and human papillomavirus status in oropharyngeal squamous cell carcinoma.

BACKGROUND: Human papillomavirus (HPV)-positive and HPV-negative oropharyngeal squamous cell carcinomas (OSCCs) are two distinct entities. We defined the molecular profiles of druggable receptor tyrosine kinases (RTKs) in both groups. MATERIALS AND METHODS: E5 expression and RTK alterations were studied in 17 HPV-positive and 59 HPV-negative formalin-fixed OSCCs. RTK activation was explored in further 12 frozen OSCCs. RESULTS: The HPV-positive OSCCs showed E5 expression and 33.3% expressed low level of HER2. The HPV-negative OSCCs showed HER2 expression (31.2%), increased HER2 gene copy number (46.51%, P = 0.045) and HER2 activation through HER2/EGFR heterodimerisation; HER3 (51.06%, P = 0.008) and neuregulin (65.63%; P = 0.03) expression, HER3 activation and HER3/EGFR heterodimerisation; and increased IGF-1R copy number (40.50%, P = 0.021), high IGF-1R cDNA values (P = 0.002), IGF-1R activation and expression of IGF1/2 and amphiregulin. PI3KCA mutations/expression/increased gene copy number and PTEN mutations were found in both groups, whereas PTEN gene loss was only observed in the HPV-positive cases. CONCLUSION: Human papillomavirus-positive and HPV-negative OSCC showed different RTK profiles. In HPV-positive cases, it would be interesting to study the expression of E5, which may modulate EGFR turnover and activate VEGF and PDGFRß. In HPV-negative cases, HER3 may be a promising druggable biomarker that deserves further investigation. PI3KCA and PTEN alterations encourage the promising clinical evaluation of PI3K/mTOR inhibitor activity in OSCC, particularly in HPV-positive/PI3KCA-mutated OSCCs because they may be driven by PI3KCA mutation alone.

[The clinical significance of thymidylate synthase expression in human papillomavirus-related oropharyngeal squamous carcinoma].

The focus of human papilloma virus (HPV), particulary HPV 16 is on the role of carcinogenic and prognostic factors on oropharyngeal squamous carcinoma (OSCC). However, it remains unclear why patients with HPV-positive tumors have better outcomes than those with HPV-negative tumors. Thymidylate synthase (TS) is one of the initial key enzymes in the 5-fluouracil (5-FU) metabolic pathway. Clinical studies showed that intratumoural TS level was related to the response to 5-FU-based chemotherapy in patients with several types of cancer such as gastroenterological and head and neck cancers. We investigated the prevalence of HPV infection and TS expression in the patients with OSCC and evaluated the prognostic implications according to the HPV status and TS expression. We evaluated for high-risk HPV types (HPV 16, 18, 31, 33, 51, 52, 58) using a real-time polymerase chain reaction (RT-PCR) assay on archival biopsies from 54 patients with OSCC. Immunohistochemical assessments for TS were also performed. HPV was positive in 22 (40.7%) of 54 samples. Of these positive cases, 21 (95%) carried HPV 16 and only 1 (5%) HPV58 sequences. TS was overexpressed in 25 (46.3%) of 54 samples. Of these, 19 (76.0%) had an HPV-negative status and 21 (84.0%) were heavy smokers. TS over-expression was associated with the patients with HPV-negative tumors (P = 0.02) and heavy smokers (p = 0.012). Univariate analysis revealed that HPV positive status (77.3% vs. 29.0%; p = 0.006) significantly improved overall survival. Conversely, no remarkable prognostic difference was observed on immunohistochemical analysis of TS expression. A multivariate analysis using Cox's proportional hazard model showed that early T stage (T1-2), early N stage (N0-1), and positive HPV status were significantly independent predictors for superior overall survival. Our studies suggested that positive HPV status was most strongly associated with a favorable prognosis in the patients with OSCC. TS expression has an unusual aspect as a biomarker for OSCC, though it was not related to prognosis.

Glutathione Peroxidase (GPx) and Superoxide Dismutase (SOD) in Oropharyngeal Cancer Associated with EBV and HPV Coinfection.

Recent reports have pointed to the link between persistent inflammation, oxidative stress, and carcinogenesis; however most of the studies concerning the role of viruses in head and neck cancer (HNC) are focused mainly on one type of virus. Our present study aimed to study the relationship between Epstein-Barr virus/human papilloma virus (EBV/HPV) coinfection and glutathione peroxidase (GPx) and superoxide dismutase (SOD) level in oropharyngeal cancer. Fresh-frozen tumor tissue samples were collected from 128 patients with oropharyngeal cancer infected with EBV or HPV or with EBV/HPV coinfection. After DNA extraction, EBV and HPV DNA was detected using a polymerase chain reaction (PCR) assay. GPx and SOD activity was determined in homogenates of cancer tissue using diagnostic kits produced by Randox Laboratories. Both GPx and SOD activity was statistically lower in patients with EBV/HPV coinfection than in a single EBV or HPV infection. Analysis of GPx and SOD activity in relation to histological grading and tumor, node (TN) classification revealed that in poorly-differentiated tumors, the level of antioxidant enzymes was lower compared with well-differentiated lesions and in cases with greater tumor dimensions and lymph-node involvement, both GPx and SOD activity was decreased. Further studies are necessary to clarify the influence of interplay between EBV, HPV, and oxidative stress on malignant transformation of upper aerodigestive tract epithelial cells.

Downregulation of the α1- and ß1-subunit of sGC in Arterial Smooth Muscle Cells of OPSCC Is HPV-Independent.

The nitric oxide (NO)-sensitive soluble guanylyl cyclase (sGC) is a heterodimeric enzyme with an α and ß subunit. NO binds to heme of the ß1-subunit of sGC, activates the enzyme in the reduced heme iron state in vascular smooth muscle cells (VSMCs), and generates cGMP-inducing vasodilatation and suppression of VSMC proliferation. In the complex tumor milieu with higher levels of reactive oxygen species (ROS), sGC heme iron may become oxidized and insensitive to NO. To change sGC from an NO-insensitive to NO-sensitive state or NO-independent manner, protein expression of sGC in VSMC is required. Whether sGCα1ß1 exists at the protein level in arterial VSMCs of oropharyngeal squamous cell carcinoma (OPSCC) is unknown. In addition, whether differences in the genetic profile between human papillomavirus (HPV)-positive and HPV-negative OPSCC contributes to the regulation of sGCα1ß1 is unclear. Therefore, we compared the effects of HPV-positive and HPV-negative OPSCC on the expression of sGCα1ß1 in arterial VSMCs from tumor-free and tumor-containing regions of human tissue sections using quantitative immunohistochemistry. In comparison to the tumor-free region, we found a decrease in expression of both α1- and ß1-subunits in the arterial VSMC layer of the tumor-containing areas. The OPSCC-induced significant downregulation of the α1- and ß1-subunits of sGC in arterial VSMC was HPV-independent. We conclude that the response of sGC to NO in tumor arterial VSMCs may be impaired by oxidation of the heme of the ß1-subunit, and thus, α1- and ß1-subunits of sGC could be targeted to degradation under oxidative stress in OPSCC in an HPV-independent manner. The degradation of sGCα1ß1 in VSMCs may result in increased proliferation of VSMCs, promoting tumor arteriogenesis in OPSCC. This can be interrupted by preserving the active heterodimer sGCα1ß1 in arterial VSMCs.

Prognostic value of ALDH2 polymorphism for patients with oropharyngeal cancer in a Japanese population.

BACKGROUND: Half of Japanese possess a polymorphism of aldehyde dehydrogenase 2(ALDH2), while few white individuals possess this mutation. The purpose of this study was to investigate the possibility of ALDH2 polymorphism as a prognostic factor for oropharyngeal cancer (OPC) among Japanese population. METHODS: We analyzed 82 Japanese patients with OPC treated between 2006 and 2011. The median observation period was 50 months. P16-staining and ALDH2 polymorphisms were investigated. To examine the frequencies of second primary pharyngeal and esophageal cancers (SPPEC),37 Japanese patients with OPC treated at Tokyo University Hospital were included for statistical analysis. RESULTS: Statistically significant differences were noted in OS among sex, age, N classification, and p16 (p = 0.045, 0.024, 0.020, 0.007, respectively). In addition, OS and DSS rates of the patients with heterozygous ALDH2 tended to be worse than those of the patients with homozygous ALDH2 (p = 0.21, 0.086, respectively). Of note, OS and DSS of the patients with p16-negative OPC and heterozygous ALDH2 was significant poorer than those of the patients with p16-positive OPC (p = 0.002, 0.006, respectively), while there was no significant difference in OS and DSS between patients with p16-positive OPC and patients with p16-negative OPC and homozygous ALDH2. CONCLUSIONS: ALDH2 polymorphism might be a promising prognostic factor for Japanese patients with p16-negative OPC.

Influence of matrix metalloproteinase 9 (MMP-9) on the metastatic behavior of oropharyngeal cancer.

BACKGROUND: The role of the single matrix metalloproteinases (MMPs) in the metastatic process of squamous cell carcinomas (SCC) is still obscure. MATERIALS AND METHODS: The MMP-9 expression was described immunohistochemically in 105 patients (40-79 years of age, mean: 57.84 years; 84 male, 21 female) suffering from orophatyngeal cancer (22x TI, 31x T2, 24x T3, 28x T4) with different neck stages (41x N0, 6x N1, 54x N2, 4x N3 neck). RESULTS: A significant correlation between MMP-9 expression and T stage (p < 0.05), N stage (r = 0.55, p < 0.01) and UICC stage (r = 0.55, p < 0.01) was revealed. Most remarkable was the high MMP-9 expression with simultaneously high UICC stages. CONCLUSION: The results give further indication that MMP-9 plays a role in the metastatic behavior of oropharyngeal SCC. It will be a project for the near future to create a standardized evaluation score of immuno-histological stainings to allow valid comparison of the results and published data.

Prognostic significance of cyclooxygenase-2 in oropharyngeal squamous cell carcinoma.

PURPOSE: To determine the relative prognostic significance of cyclooxygenase (COX)-2 expression in patients with oropharyngeal squamous cell carcinoma (SCC). EXPERIMENTAL DESIGN: This retrospective cohort study included 82 patients with SCC referred to the Department of Therapeutic Radiology at Yale-New Haven Hospital (Connecticut) between 1980 and 1999 who were treated with primary external beam radiotherapy or gross total surgical resection and postoperative radiotherapy. A microarray of archival tumor tissue was constructed and stained with monoclonal antibodies directed against COX-2 and scored for intensity by a pathologist blinded to the clinical outcomes of the patients. COX-2 immunoreactivity and clinicopathological data were analyzed with respect to survival endpoints using bivariate and multivariate techniques. RESULTS: Frequency of COX-2 overexpression was 45%. In multivariate analysis, COX-2 positivity predicted poor 3-year survival (P = 0.02; odds ratio = 0.41; 95% confidence interval, 0.20-0.84). Increasing age was significantly associated with increased 3-year survival (P = 0.03; odds ratio = 1.04; 95% confidence interval, 1.004-1.09). Positive COX-2 status trended toward predicting decreased 3-year disease-free survival. CONCLUSIONS: COX-2 was the most important predictor of poor survival in this patient cohort. In patients with oropharyngeal SCC treated with external-beam radiation therapy, overexpression of COX-2 may affect clinical outcome, and COX-2 may therefore prove valuable both as a prognostic factor and as a therapeutic target.

Tissue fatty acid composition and secretory phospholipase-A2 activity in oral squamous cell carcinoma.

PURPOSE: Oral squamous cell carcinoma (OSCC) is a remarkable health problem worldwide, but its pathogenesis remains unknown. The aim of this study was to compare fat composition and secretory phospholipase-A2 (sPLA2) activity between the malignant and adjacent normal squamous tissues in patients with OSCC. METHODS: Paired samples of malignant squamous and adjacent normal-appearing tissues were collected from 27 patients with OSCC. The fatty acid composition in the obtained tissues was determined by gas liquid chromatography. Tissue enzyme activities of sPLA2 were measured using the standard assay with Diheptanoyl Thio-Phosphatidylcholine as substrate. RESULTS: In the OSCC tissue, the level of stearic acid (18:0) and activity of sPLA2 were higher (P < 0.001), and the levels of oleic acid (18:1n-9) and linoleic acid (18:2n-6) were lower than that in the adjacent normal-appearing squamous tissue (P < 0.001). The activity of sPLA2 in OSCC was strongly negatively correlated with the amount of 18:2n-6 (r = -0.41, P < 0.001). Negative significant associations were observed between the OSCC invasion and tissue levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHE). CONCLUSION: The changes in the fatty acid composition and sPLA2 activity may be regarded as indicators of altered lipid metabolism occurring in vivo during squamous cell carcinogenesis.

Overexpression of transfected human ribonucleotide reductase M2 subunit in human cancer cells enhances their invasive potential.

The ribonucleotide reductase (RR) gene has been associated with malignant transformation and metastatic potential. In this report, the significance of the expression of RR mRNA and enzymatic activity to the invasive potential was examined by Boyden chamber invasion assay. Our results suggest that overexpression of RR M2 mRNA and RR enzymatic activity correlates to an increase in cell invasive potential. The drug-induced HURs clone expressed a higher level RR M2 mRNA and enzyme activity which contributes significantly to the 3-fold increase in invasive potential of the cells observed relative to the KB wild-type control. On the contrary, the HUr revertant clone decreased the RR M2 mRNA level and enzymatic activity, concomitantly decreasing their invasive potential. This phenomenon is most likely due to the return of RR to levels comparable to that of the KB wild-type cells. To confirm that this observation was not of a drug-resistance phenotype associated with multiple gene alterations, the panel of RR transfectants (M1-D transfected M1 subunit cDNA, M2-D transfected M2 subunit cDNA, X-D transfected M1/M2 cDNA) characterized in a previous study were also tested in the invasion assay. The M2-D clone expressed 6-fold higher RR M2 mRNA and RR activity and also demonstrated 6-fold higher invasive potential in vitro than either the parental or vector only transfected cell line (KB-V). The X-D clone demonstrated 3-fold higher M2 mRNA expression and revealed 4-fold higher invasive potential than control cells. The M1-D clone, in contrast, expressed a baseline level of RR M2 mRNA and higher M1 mRNA. In contrast to the X-D and M2-D cells, the invasive potential of M1-D reached an even lower level in the invasive assay than the control. These results, therefore, suggest that RR M2 overexpression plays an important role in a tumor's invasiveness.

Drug-metabolizing enzymes in pharyngeal mucosa and in oropharyngeal cancer tissue.

Cytochrome P4501A1 (CYP1A1) and the UDP-glucuronosyltransferase isoform UGT1A6 were studied in pharyngeal mucosa and squamous cancer tissue obtained from 27 male subjects (10 healthy nonsmoking volunteers, 10 smokers, and 7 smokers with pharyngeal cancer). CYP1A activity (7-ethoxyresorufin O-deethylase) was significantly induced in smokers as compared to nonsmokers (2.3 +/- 1.1 and 0.8 +/- 0.4 pmol x min[-1] x mg protein[-1], respectively). Immunoblot analysis demonstrated enhanced CYP1A1 protein in smokers. UGT activity towards 4-methylumbelliferone and 1-naphthol was also detectable in oropharyngeal mucosa. RT-PCR (reverse transcriptase-polymerase chain reaction) analysis indicated that UGT activity was at least in part due to the expression of UGT1A6. In cancer tissue, CYP1A activity was decreased in comparison with surrounding healthy mucosa (1.2 +/- 0.9 in tumor tissue vs. 2.2 +/- 0.7 pmol x min[-1] x mg protein[-1], respectively), whereas means and medians of UGT activity were unchanged. The results suggest that phase I and II drug-metabolizing enzymes are detectable in oropharyngeal mucosa and that CYP1A activity is inducible by constituents of cigarette smoke.

Ornithine decarboxylase activity in tumor and normal tissue of head and neck cancer patients.

Tumorigenesis requires increased biosynthesis of polyamines and elevated levels of ornithine decarboxylase, which is the rate-limiting enzyme in the polyamine synthesis pathway. Previous animal studies have noted a marked increase in ornithine decarboxylase after exposure to tumorigenic stimuli and that pretreatment with vitamins A and E provides protection against the carcinogenic action. However, studies of ornithine decarboxylase activity in human oral cavity carcinoma have not been as specific. The goal of this study was to determine whether a specific difference in ornithine decarboxylase activity occurs in tumor versus adjacent normal tissue in head and neck squamous cell carcinoma patients. Ornithine decarboxylase activity was measured in 30 consecutive head and neck cancer patients undergoing surgical therapy. Ornithine decarboxylase levels were found to be significantly elevated in tumor tissue samples when compared to adjacent normal mucosa samples (P less than .004). This finding confirms the previous findings noted in animal models and implies that the protective effects of vitamins A and E will extend to human head and neck cancers.

Inducible nitric oxide synthase expression in pharyngeal squamous cell carcinoma: relation to p53 expression, clinicopathological data, and survival.

OBJECTIVE: To investigate the expression of inducible nitric oxide synthase (iNOS) in oropharyngeal and hypopharyngeal squamous cell carcinoma (SCC) and its relation to p53 expression, histologic differentiation, clinical data, and prognosis. STUDY DESIGN: A retrospective survey. METHODS: Primary tumors for analyses were obtained from 118 patients diagnosed with SCC of the oropharynx or hypopharynx between 1975 and 1998 in eastern Finland. Immunohistochemical analysis was used to evaluate the expression of iNOS and p53. The expression pattern of iNOS was related to p53 expression, clinical data, and survival. RESULTS: High iNOS score was associated significantly with high nuclear p53 expression index (P = .006) and positive cytoplasmic p53 expression (P = .025). The score for iNOS expression was significantly lower in the largest (T4) tumors (P = .043). No association was seen between iNOS score and N or M class, tumor stage, or histologic differentiation. The score for iNOS expression was not related to overall survival. CONCLUSIONS: The expressions of iNOS and p53 seem to be inter-related in pharyngeal SCC, although the causality remains to be clarified. The expression of iNOS shows no prognostic value in pharyngeal SCC.

Placental glutathione S-transferase isoenzyme expression during promotion of two-stage hamster cheek-pouch carcinogenesis.

Glutathione S-transferases (GSTs) are the products of a multigene family. A well-established function of GSTs is to metabolize carcinogens by catalysing the conjugation of electrophilic substrates to glutathione. Whether placental GST (GST-P) is expressed during the promotion of two-stage hamster buccal-pouch mucosa (HBPM) carcinogenesis was investigated here, using 7,12-dimethylbenz[a]anthracene (DMBA) as the initiator and 12-O-tetradecanoylphorbol-13-acetate (TPA) as the promoter. Cytoplasmic and nuclear staining for GST-P was seen in pouches treated with DMBA for 4 or 16 weeks, as well as in those treated with DMBA for 4 weeks and then TPA for 12 weeks. No GST-P positivity was seen in any pouches treated with only TPA or with mineral oil for either 4 or 16 weeks. The average number of GST-P-stained foci in the groups treated with DMBA for 16 weeks (246 +/- 96; mean +/- SD) or DMBA for 4 weeks followed by TPA for 12 weeks (186 +/- 67) was significantly higher than in pouches treated with only DMBA for 4 weeks (97 +/- 24). These results demonstrate that TPA alone is not sufficient for GST-P expression in hamster buccal pouch mucosa. However, after being initiated with DMBA, then promoted with TPA, GST-P activity is induced in hamster buccal pouch mucosa during squamous-cell carcinogenesis. This underpins the suggestion that GST-P may play an important part during the promotion stage of oral carcinogenesis.

Polymorphisms of xenobiotic metabolizing genes in oropharyngeal carcinoma.

OBJECTIVE: The objective was to determine the prevalence of the polymorphisms of the microsomal epoxide hydrolase (Ephx1), glutathione S-transferase mu1 (GSTM ), theta1 (GSTT1), and pi1 (GSTP1) genes in patients with oropharyngeal carcinoma. STUDY DESIGN: Gene polymorphisms in 137 patients with oropharyngeal carcinoma were determined by polymerase chain reaction and restriction enzyme digestion for xenobiotic metabolizing enzymes that have been implicated in the carcinogenesis of tobacco-related neoplasias and compared with a population sample of 99 persons. RESULTS: At Ephx1 (microsomal epoxide hydrolase) codon 113, an overrepresentation of the greater activity genotype (Tyr/Tyr) was observed for male ever-smokers alone, both male and female ever-smokers, female never-smokers alone, and in both male and female never-smokers, compared with a control population sample. At codon 139, Ephx1 showed no differences. There was an overrepresentation of homozygosity for the GSTT1 (glutathione S-transferase theta1) null allele [but not for the GSTM1 (glutathione S-transferase mu1) null allele] in ever-smokers, when compared with controls. Polymorphisms at the GSTP1 (glutathione S-transferase pi1) locus did not show differences versus controls, although in the never-smoker cancer sample there was a higher prevalence of the B/B genotype compared with ever-smokers. CONCLUSION: The Ephx1 codon 113 Tyr/Tyr variant, as well as homozygosity for the GSTT1 null allele, is associated with oropharyngeal carcinogenesis.

Glutathione peroxidases in human head and neck cancer.

Glutathione peroxidases (GPX), enzymes that catalyze the reduction of reactive intermediates have been implicated in the action of several cytostatic drugs. Two major types of GPX have been found: a selenium-dependent form (SeGPX) which is active with both hydrogen peroxide and organic hydroperoxides, and a selenium-independent GPX which is only active with organic hydroperoxides. SeGPX and total GPX (tGPX) activity were assayed in cytosolic fractions from malignant and adjacent normal tissue in 13 patients with oral/oropharyngeal, and 10 patients with laryngeal squamous cell carcinoma. Neck lymph node metastases were available from 2 and 5 of these patient respectively. Tumors from the oral/oropharyngeal region contained significantly less SeGPX and tGPX activity than laryngeal tumors. Primary oral/oropharyngeal and laryngeal tumors had lower SeGPX activities than the matched normal mucosa. tGPX activities were similar in normal and tumor tissue. Metastases contained slightly more SeGPX and tGPX activity than the matched tumor tissue. We conclude that the inherent anti-tumor drug resistance of human neck squamous cell carcinoma is not mediated by increased glutathione peroxidase enzyme activity in the tumor tissue.

Serum leucine aminopeptidase in head and neck cancer.

Serum leucine aminopeptidase (LAP) activity was assayed in patients with head and neck cancer. The levels were found to be significantly higher than the controls. However, the rise in serum LAP was nearly the same in all patients studied, irrespective of the character or histopathology of the lesion but varied with respect to the site involved, i.e. from about 40 per cent in cancer of the hypopharynx to more than 100 per cent in cancer of the nasopharynx. Serum LAP activity was found to increase with the extent of the lymph node spread. After treatment the levels were found to be reduced.

AKT in stromal fibroblasts controls invasion of epithelial cells.

The tumour microenvironment has an important role in cancer progression and recent reports have proposed that stromal AKT is activated and regulates tumourigenesis and invasion. We have shown, by immuno-fluorescent analysis of oro-pharyngeal cancer biopsies, an increase in AKT activity in tumour associated stromal fibroblasts compared to normal stromal fibroblasts. Using organotypic raft co-cultures, we show that activation of stromal AKT can induce the invasion of keratinocytes expressing the HPV type 16 E6 and E7 proteins, in a Keratinocyte Growth Factor (KGF) dependent manner. By depleting stromal fibroblasts of each of the three AKT isoforms independently, or through using isoform specific inhibitors, we determined that stromal AKT2 is an essential regulator of invasion and show in oro-pharyngeal cancers that AKT2 specific phosphorylation events are also identified in stromal fibroblasts. Depletion of stromal AKT2 inhibits epithelial invasion through activating a protective pathway counteracting KGF mediated invasions. AKT2 depletion in fibroblasts stimulates the cleavage and release of IL1B from stromal fibroblasts resulting in down-regulation of the KGF receptor (fibroblast growth factor receptor 2B (FGFR2B)) expression in the epithelium. We also show that high IL1B is associated with increased overall survival in a cohort of patients with oro-pharyngeal cancers. Our findings demonstrate the importance of stromal derived growth factors and cytokines in regulating the process of tumour cell invasion.

ALDH1-positive cancer stem-like cells are enriched in nodal metastases of oropharyngeal squamous cell carcinoma independent of HPV status.

Oropharyngeal squamous cell carcinoma (OSCC) is caused by high-risk (HR) human papillomavirus (HPV) or alcohol and tobacco abuse. Aldehyde dehydrogenase 1 (ALDH1) is a confirmed marker for cancer stem-like cells (CSCs) of OSCC responsible for therapy resistance, recurrence and metastasis. Associations between HR-HPV/p16, CSC frequency and clinicopathological parameters in patients with metastatic OSCC were investigated. In the present study, HPV genotypes and expression of ALDH1 and p16 was analyzed in 40 paired OSCC and metastases. A significant correlation between ALDH1 positivity with lower primary tumor differentiation grade (P=0.009) and higher nodal status (P=0.015) was noted. Compared to primary tumors, the proportion of ALDH1-expressing cells was significantly increased in metastases (P=0.012), while significantly fewer ALDH1-expressing cells were found in HR-HPV-DNA⁺/p16⁺ primary tumors (P=0.038) compared to HR-HPV-DNA⁻/p16⁻ primary tumors. Metastases showed no difference. ALDH1⁺ CSCs are detectable in OSCC and metastases. ALDH1 high-grade OSCC exhibits a more aggressive phenotype characterized by higher nodal classification and lower differentiation. This suggests a subpopulation contained in the ALDH1-positive OSCC cell pool able to complete the metastatic cascade and subsequently enriching in metastasis independent of tumor etiology and ALDH1 content.

The role of metalloendopeptidases in oropharyngeal carcinomas assessed by tissue microarray.

The goal of this study was to investigate the expression of some metalloendopeptidases in squamous cell carcinomas of the oropharynx as well as its relation to histological differentiation, staging of disease, and prognosis. Paraffin blocks from 21 primary tumors were obtained from archives of the Department of Pathology, Paulista Medical School, Federal University of Sao Paulo, UNIFESP/EPM. Immunohistochemistry was used to detect the expression of EP24.15 and EP24.16 by means of tissue microarrays. Expression of EP24.15 or EP24.16 was not correlated with the stage of disease, histopathological grading or recurrence in squamous cell carcinomas of the oropharynx. In summary, our results support the notion that EP24.15 and EP24.16 are expressed in carcinoma of the oropharynx; however, these do not appear to be suitable biomarkers for histological grading, disease stage or recurrence as depicted by tissue microarrays and immunohistochemistry.