c-Met expression as an indicator of survival outcome in patients with oral tongue carcinoma

Molecular signaling in cancer stem cells of tongue squamous cell carcinoma: Therapeutic implications and challenges

Head and neck squamous cell carcinoma is the seventh most common cancer worldwide with high mortality rates. Amongst oral cavity cancers, tongue carcinoma is a very common and aggressive oral cavity carcinoma. Despite the implementation of a multimodality treatment regime including surgical intervention, chemo-radiation as well as targeted therapy, tongue carcinoma shows a poor overall 5-year survival pattern, which is attributed to therapy resistance and recurrence of the disease. The presence of a rare population, i.e., cancer stem cells (CSCs) within the tumor, are involved in therapy resistance, recurrence, and distant metastasis that results in poor survival patterns. Therapeutic agents targeting CSCs have been in clinical trials, although they are unable to reach into therapy stage which is due to their failure in trials. A more detailed understanding of the CSCs is essential for identifying efficient targets. Molecular signaling pathways, which are differentially regulated in the CSCs, are one of the promising targets to manipulate the CSCs that would provide an improved outcome. In this review, we summarize the current understanding of molecular signaling associated with the maintenance and regulation of CSCs in tongue squamous cell carcinoma in order to emphasize the need of the hour to get a deeper understanding to unravel novel targets.

Can Immunoexpression of Cancer Stem Cell Markers Prognosticate Tongue Squamous Cell Carcinoma? A Systematic Review and Meta-Analysis

The objective was to evaluate the association of the immunoexpression of cancer stem cell (CSC) markers with clinicopathological and survival outcomes in tongue squamous cell carcinoma (TSCC) patients. This systematic review and meta-analysis [PROSPERO (CRD42021226791)] included observational studies that compared the association of clinicopathological and survival outcomes with CSC immunoexpression in TSCC patients. Pooled odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CI) were used as outcome measures. Six studies identified the association with three surface markers (c-MET, STAT3, CD44) and four transcription markers (NANOG, OCT4, BMI, SOX2). The odds of early-stage presentation were 41% (OR = 0.59, 95% CI 0.42-0.83) and 75% (OR = 0.25; 95% CI 0.14-0.45) lower in CSC and SOX2 immuno-positive cases than immuno-negative cases, respectively. The odds of well-differentiated tumors in transcription marker immuno-positive cases were 45% lower compared to immuno-negative cases (OR = 0.55, 95% CI 0.32-0.96). The odds of positive lymph nodes were 2.01 times higher in CSC immuno-positive cases compared to immuno-negative cases (OR = 2.01, 95% CI 1.11-3.65). Mortality in immuno-positive cases was 121% higher than that in immuno-negative cases (HR = 2.21; 95% CI 1.16-4.21). Advanced tumor staging and grading, lymph node metastasis, and mortality were significantly associated with positive immunoexpression of CSC markers.

Age and risk of recurrence in oral tongue squamous cell carcinoma: Systematic review

The incidence of oral tongue squamous cell carcinoma has been increasing in young patients (≤45 years) without a clear etiologic driver. It is unknown if younger patients have an increased risk of recurrence compared to older patients. A literature search was conducted through January 2020 using PubMed/MEDLINE, Embase, Cochrane, Scopus, Science Direct, and clinicaltrials.gov. This review was registered with PROSPERO (ID: CRD42020167498) and the PRISMA statement was followed. Studies were eligible for inclusion if they assessed risk of recurrence by age using a time-to-event analysis, used an age cutoff of ≤45 years or less for the younger cohort, and limited the analysis to the oral tongue subsite. Data were extracted independently by two reviewers using a form with a prespecified list of variables. There were 13 articles that met criteria for the qualitative synthesis (n = 1763 patients). The reported 5-year rates of disease-free survival ranged from 30% to 72% for the younger cohorts and 42% to 81% for the older cohorts. Three studies reported a statistically significant increased risk of recurrence in younger patients, three studies reported a nonsignificant increased risk in younger patients, and seven studies reported a similar risk in younger patients based on the time-to-event analyses. There may be an increased risk of recurrence for younger patients with oral tongue cancer. A definitive conclusion is precluded by limitations among individual studies, and additional research is warranted to examine this question.

Co-expression of EGFR and MET has a synergistic effect on the prognosis of patients with oral squamous cell carcinoma

BACKGROUND

This study aimed to elucidate the correlation between gene amplification, protein expression of receptor tyrosine kinase, and prognosis of patients with oral squamous cell carcinoma (OSCC) using immunohistochemistry (IHC) and next-generation sequencing data.

METHODS

We evaluated data pertaining to 208 patients with OSCC using IHC for epidermal growth factor receptor (EGFR) and mesenchymal-epithelial transition factor (MET).

RESULTS

High expressions of EGFR and MET were detected in 60 and 41 patients, respectively. We evaluated the association of clinicopathological variables with high expressions of EGFR and/or MET. Distant metastasis was found in 9 of 41 patients (22.0%) and 6 of 15 patients (40.0%) with high expression of MET and high co-expressions of EGFR and MET, respectively; statistically significant differences were detected in both high expression of MET (P = .003) and high co-expressions of EGFR and MET (P = 3.41 × 10^-5 ). The cumulative 5-year survival rate of patients with high and low expressions of EGFR or MET was approximately 65% and 85%, respectively. Conversely, among cases with high expressions of EGFR or MET, there was no additional decrease in the survival rate of patients harboring TP53 mutations. Moreover, the survival rate of patients with high co-expression of both EGFR and MET was very poor (22.0%) (P < 1.0 × 10^-9 ).

CONCLUSION

Our findings suggest that evaluation of protein expressions of EGFR and MET may facilitate prognostic assessment of patients with OSCC; in addition, patients with OSCC should be screened for enrollment in clinical trials of combination therapy with EGFR and MET inhibitors.

Role of c-Met expression on prognosis of head and neck cancer: A literature review and meta-analysis

The prognostic role of c-Met expression in patients with head and neck cancer were controversial among different studies. Thus, we performed a meta-analysis to evaluate the relationships between c-Met expression and survival and clinical parameters of head and neck cancer patients. Summary hazard ratio (HR) and 95% confidence intervals (CIs) were calculated to analyze the correlations between c-Met expression and overall survival (OS), and disease-free survival (DFS). Furthermore, odds ratios (ORs) and 95% CIs were used to describe the relationships between c-Met expression and different clinicopathological parameters. A total of 2417 patients from 19 studies were enrolled in the final analysis. The results showed that patients with higher c-Met expression had a poor OS (HR, 1.65; 95% CI, 1.20-2.27) and DFS (HR, 1.48; 95% CI, 0.99-2.20). In addition, c-Met expression was associated with the N classification of patients with head and neck cancer. These results suggested that c-Met expression was a risk factor for head and neck cancer, and increased c-Met expression would be a predictor of a poorer prognosis for the patients.

Prognostic role of c-Met in head and neck squamous cell cancer tissues: a meta-analysis

This meta-analysis aims to evaluate the effects of high c-Met levels in head and neck squamous cell carcinomas (HNSCC) on survival and clinicopathological features. Publications concerned with the clinical significance of c-Met protein expression in HNSCC were identified from the Scopus and Web of Science database searches. To elucidate the relationship between c-Met expression and clinical outcomes, a meta-analysis of the selected articles was conducted. Seventeen publications involving a total of 1724 patients met the inclusion criteria. c-Met overexpression was significantly correlated with poor overall survival (hazard ratio (HR) = 2.19, 95% confidence interval (CI) = 1.55-3.10). c-Met immunohistochemical staining positivity was also associated with worse relapse-free survival (HR = 1.64, 95% CI = 1.24-2.17) and presence of regional lymph node metastases (odds ratio (OR) = 1.76, 95% CI = 1.26-2.45). High levels of c-Met expression in HNSCC predict unfavorable prognosis associated with common clinicopathological features.

FoxM1 promotes epithelial-mesenchymal transition, invasion, and migration of tongue squamous cell carcinoma cells through a c-Met/AKT-dependent positive feedback loop

Supplemental Digital Content is available in the text.

Forkhead box protein M1 (FoxM1) has been associated with cancer progression and metastasis. However, the function of FoxM1 in tongue squamous cell carcinoma (TSCC) remains largely unknown. The purpose of this study was to determine the role of FoxM1 in regulation of epithelial–mesenchymal transition (EMT) and migration of TSCC cells. We found that FoxM1 induced EMT and increased invasion/migration capacity in SCC9 and SCC25 cells. FoxM1 stimulation increased c-Met, pAKT, and vimentin levels but decreased E-cadherin level. Chromatin immunoprecipitation assay established that FoxM1 is bound to the promoter of c-Met to activate its transcription. In turn, c-Met promoted the expression of FoxM1 and pAKT. Blocking AKT signaling attenuated the invasion and migration of SCC9 and SCC25 cells stimulated by FoxM1 or c-Met. These results indicate that a positive feedback loop controls the EMT and migration of TSCC cells induced by FoxM1 and c-Met through AKT. Furthermore, the expression levels of FoxM1, pAKT, and c-Met were found to significantly increase in TSCC tissues compared with normal tissues, and these three biomarkers were concomitantly expressed in TSCC tissues. Clinical association analyses indicated that the expression of FoxM1, c-Met, and pAKT was associated with clinicopathological characteristics of patients with TSCC including tumor stage, tumor size, and lymph node metastasis. Taken together, our findings suggest that FoxM1 promotes the EMT, invasion and migration of TSCC cells, and cross-talks with c-Met/AKT signaling to form a positive feedback loop to promote TSCC development.

Absent and abundant MET immunoreactivity is associated with poor prognosis of patients with oral and oropharyngeal squamous cell carcinoma

Although the receptor tyrosine kinase (RTK) MET is widely expressed in head and neck squamous cell carcinoma (HNSCC), its prognostic value remains unclear. This might be due to the use of a variety of antibodies and scoring systems. Here, the reliability of five commercial C-terminal MET antibodies (D1C2, CVD13, SP44, C-12 and C-28) was evaluated before examining the prognostic value of MET immunoreactivity in HNSCC. Using cancer cell lines, it was shown that D1C2 and CVD13 specifically detect MET under reducing, native and formalin-fixed paraffin-embedded (FFPE) conditions. Immunohistochemical staining of routinely FFPE oral SCC with D1C2 and CVD13 demonstrated that D1C2 is most sensitive in the detection of membranous MET. Examination of membranous D1C2 immunoreactivity with 179 FFPE oral and oropharyngeal SCC – represented in a tissue microarray – illustrated that staining is either uniform (negative or positive) across tumors or differs between a tumor's center and periphery. Ultimately, statistical analysis revealed that D1C2 uniform staining is significantly associated with poor 5-year overall and disease free survival of patients lacking vasoinvasive growth (HR = 3.019, p < 0.001; HR = 2.559, p < 0.001). These findings might contribute to reliable stratification of patients eligible for treatment with biologicals directed against MET.

High expression of c-Met and EGFR is associated with poor survival of patients with glottic laryngeal squamous cell carcinoma

The present study was undertaken to explore the association between the expression of hepatocyte growth factor receptor (c-Met) and epidermal growth factor receptor (EGFR) with clinicopathological factors and survival status, to obtain prognostic biomarkers in patients with glottis laryngeal squamous cell carcinoma (GLSCC). The expression status of c-Met and EGFR protein was analyzed in 71 archival laryngeal cancer samples by immunohistochemistry. Statistical methods, including univariate and multivariate Cox regression analysis, were used to determine risk factors of progression. In addition, survival analysis was performed by the Kaplan-Meier method. The present study detected positive expression of c-Met and EGFR in 69.0 and 91.5% of GLSCC samples, respectively. The median disease-free survival (DFS) and overall survival (OS) times of all patients were 42.4 and 81.8 months, respectively, and the 2-year DFS and OS rates were 60.1 and 84.91%, respectively. Univariate Cox regression analysis revealed that patients with high expression of EGFR or c-Met had a predisposition for tumor recurrence. The expression of c-Met expression was significantly associated with that of EGFR (P=0.001). High expression of c-Met or EGFR was associated with shorter DFS and OS times. Findings of the multivariate Cox regression analysis indicated that c-Met-expression may be used as an independent predictor of DFS and OS (P=0.002 and P=0.008, respectively). However, EGFR expression was not an independent predictor for DFS and OS (P=0.352 and P=0.24, respectively). The high expression of c-Met and EGFR was associated with poor survival and are important predictors for prognosis of patients with GLSCC.

Clinicopathological impacts of high c-Met expression in head and neck squamous cell carcinoma: a meta-analysis and review

High c-Met expression has been observed in head and neck squamous cell carcinoma (HNSCC). However, its clinicopathological impact remains controversial. We performed this meta-analysis to evaluate the pathologic and prognostic impacts of c-Met overexpression in patients with HNSCC. A systematic computerized search of the electronic databases was carried out. From 16 studies, 1,948 patients with HNSCC were included in the meta-analysis. Compared with HNSCCs showing low c-Met expression, tumors with high c-Met expression were significantly associated with higher rate of lymph node metastasis (odds ratio = 3.26, 95% CI: 2.27–4.69, P < 0.00001) and higher T stage (odds ratio = 1.33, 95% CI: 1.03–1.71, P = 0.03). In addition, patients with c-Met-high HNSCC showed significantly worse disease-free survival (hazard ratio = 1.49, 95% CI: 1.04–2.14, P = 0.03) and overall survival (hazard ratio = 1.83, 95% CI: 1.29–2.60, P = 0.0007) than those with c-Met-low tumor. In conclusion, this meta-analysis demonstrates that high c-Met expression is significantly associated with worse pathological features and prognosis, indicating c-Met overexpression is an adverse prognostic marker for patients with HNSCC.

Prognostic value of c-MET in head and neck cancer: A systematic review and meta-analysis of aggregate data

OBJECTIVES

The hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor (c-MET) ligand/receptor axis has been implicated in pathogenesis of malignant diseases including squamous cell carcinoma of the head and neck (SCCHN). Overexpression of c-MET has been reported as a common molecular abnormality in SCCHN, although its prognostic and predictive value remains to be validated.

METHODS

We systematically searched literature for studies evaluating c-MET expression on immunohistochemistry in newly diagnosed, non-metastatic SCCHN. The c-MET expressing cases were classified into three categories according to predefined cut-off values for positivity. Our aim was to assess the prevalence of c-MET expression and its relationship with selected clinicopathological variables.

RESULTS

Twenty-eight studies with 2019 cases were included. Relative frequencies of c-MET expression above cut-off levels I, II, and III were 81.8%, 63.8%, and 46.2%, respectively. Differences between these three values were statistically significant (p<1.0×10^-6). Above cut-off level II, c-MET positivity was associated with worse overall survival (p=4.0×10^-6), positive nodal status (p=1.0×10^-4), higher disease stage (p=7.0×10^-4), older age (p=2.1×10^-3), disease recurrence (p=2.0×10^-2), and primary tumour localization in the oral cavity (p=2.3×10^-2). Above cut-off level III, c-MET positivity was associated with worse disease-free or progression-free survival (p=9.0×10^-6), p16 negativity (p=2.4×10^-4), worse overall survival (p=4.0×10^-4), positive epidermal growth factor receptor (EGFR) status (p=7.2×10^-4), and larger primary tumours (p=4.6×10^-3).

CONCLUSION

In SCCHN, immunohistochemical overexpression of c-MET above cut-off levels III and particularly II was associated with inferior survival outcomes and advanced disease. Moreover, it represents a promising predictive biomarker for c-MET targeting, yet the optimal scoring method remains to be defined.

Implication of the Receptor Tyrosine Kinase AXL in Head and Neck Cancer Progression

Head and neck squamous cell carcinoma (HNSCC) remains a clinical challenge and identification of novel therapeutic targets is necessary. The receptor tyrosine kinase AXL has been implicated in several tumor entities and a selective AXL small molecule inhibitor (BGB324) is currently being tested in clinical trials for patients suffering from non-small cell lung cancer or acute myeloid leukemia. Our study investigates AXL expression during HNSCC progression and its use as a potential therapeutic target in HNSCC. AXL protein expression was determined in a HNSCC cohort (n = 364) using immunohistochemical staining. For functional validation, AXL was either overexpressed or inhibited with BGB324 in HNSCC cell lines to assess proliferation, migration and invasion. We found AXL protein expression increasing during tumor progression with highest expression levels in recurrent tumors. In HNSCC cell lines in vitro, AXL overexpression increased migration as well as invasion. Both properties could be reduced through treatment with BGB324. In contrast, proliferation was neither affected by AXL overexpression nor by inhibition with BGB324. Our patient-derived data and in vitro results show that, in HNSCC, AXL is important for the progression to more advanced tumor stages. Moreover, they suggest that AXL could be a target for precision medicine approaches in this dismal tumor entity.

The Dual Inhibition of Met and EGFR by ME22S, a Novel Met/EGFR Bispecific Monoclonal Antibody, Suppresses the Proliferation and Invasion of Laryngeal Cancer

PURPOSE

It has been reported that the abnormal activation of receptor tyrosine kinases is associated with the development of many human carcinomas and the high activation of EGFR and Met mediates the tumorigenicity of laryngeal carcinoma. In this study, we have done the therapeutic efficacy of ME22S (a novel EGFR/Met bispecific antibody) in laryngeal carcinoma in vitro and in vivo was thoroughly evaluated.

METHODS

The effects of ME22S on cell viability was assessed through MTT assays, and then Western blotting and immunocytochemistry were used to determine the expression of EGFR and Met. Also, wound healing and invasion assays were performed to observe the inhibitory effects of ME22S.

RESULTS

We found the ability of ME22S reducing the expression of both EGFR and Met and significantly inhibiting the cell migration, invasion, and proliferation of SNU899 and HN3 in vitro. Also, the notably reduced levels of p-Met, p-ERK, and p-AKT were found when the cells were treated with only ME22S alone or with HGF together. Meanwhile, ME22S, interestingly enough, caused caspase-3-dependent apoptotic cell death when HN3 cells were treated with ME22S for 72 h, decreased the HGF-induced Slug expression, and also inhibited the tumor growth of HN3 cells in a xenograft model in vivo.

CONCLUSIONS

Taken together, our findings suggest that the dual inhibition of EGFR and Met through ME22S largely suppresses the invasion and growth of laryngeal carcinoma both in vitro and in vivo, hence, can be a practical approach as a novel therapeutic strategy for the treatment of laryngeal carcinoma.

Is c-Met oncoprotein expression an adverse prognosticator in extrahepatic bile duct cancer treated with curative resection followed by adjuvant chemoradiotherapy?

PURPOSE

To analyze the expression of c-Met, and to investigate correlations between the expression of c-Met, clinicopathologic variables, and survival in patients undergoing curative surgery followed by adjuvant chemoradiotherapy for extrahepatic bile duct (EHBD) cancer.

METHODS

Ninety EHBD cancer patients who underwent curative resection followed by adjuvant chemoradiotherapy were enrolled. Expression of c-Met was assessed with immunohistochemical staining on tissue microarray. The correlation between clinicopathologic variables and survival outcomes was evaluated using Kaplan-Meier method and Cox proportional hazard model.

RESULTS

On univariate analysis, 66 patients (76.7 %) showed c-Met expression. c-Met expression had a significant impact on 5-year overall survival (OS) (43.0 % in c-Met(+) vs. 25.0 % in c-Met(-), p = 0.0324), but not on loco-regional relapse-free survival or distant metastasis-free survival (DMFS). However, on multivariate analysis incorporating tumor location and nodal involvement, survival difference was not maintained (p = 0.2940). Tumor location was the only independent prognostic factor predicting OS (p = 0.0089). Hilar location tumors, nodal involvement, and poorly differentiated tumors were all identified as independent prognostic factors predicting inferior DMFS (p = 0.0030, 0.0013, and 0.0037, respectively).

CONCLUSIONS

This study showed that c-Met expression was not associated with survival outcomes in EHBD cancer patients undergoing curative resection followed by adjuvant chemoradiotherapy. Further studies are needed to fully elucidate the prognostic value of c-Met expression in these patients.

Activation of MET pathway predicts poor outcome to cetuximab in patients with recurrent or metastatic head and neck cancer

BACKGROUND

Activation of the MET oncogene promotes tumor growth, invasion and metastasis in several tumor types. Additionally, MET is activated as a compensatory pathway in the presence of EGFR blockade, thus resulting in a mechanism of resistance to EGFR inhibitors.

METHODS

We have investigated the impact of HGF and MET expression, MET activation (phosphorylation), MET gene status, and MET-activating mutations on cetuximab sensitivity in recurrent or metastatic squamous cell carcinoma of the head and neck (HNSCC) patients.

RESULTS

A single-institution retrospective analysis was performed in 57 patients. MET overexpression was detected in 58% patients, MET amplification in 39% and MET activation (p-MET) in 30%. Amplification was associated with MET overexpression. Log-rank testing showed significantly worse outcomes in recurrent/metastatic, MET overexpressing patients for progression-free survival and overall survival. Activation of MET was correlated with worse PFS and OS. In multivariate logistic regression analysis, p-MET was an independent prognostic factor for PFS. HGF overexpression was observed in 58% patients and was associated with MET phosphorylation, suggesting a paracrine activation of the receptor.

CONCLUSIONS

HGF/MET pathway activation correlated with worse outcome in recurrent/metastatic HNSCC patients. When treated with a cetuximab-based regimen, these patients correlated with worse outcome. This supports a dual blocking strategy of HGF/MET and EGFR pathways for the treatment of patients with recurrent/metastatic HNSCC.

Clinical Significance of MET Gene Copy Number in Patients with Curatively Resected Gastric Cancer

The present study analyzed the prognostic impact of MET gene copy number in patients with curatively resected gastric cancer who received a combination regimen of cisplatin and S-1. The MET gene copy number was analyzed by use of quantitative real-time polymerase chain reaction. From January 2006 to July 2010, 70 tumor samples from 74 patients enrolled in a pilot study were analyzed. According to a cutoff MET gene copy number of ≥2 copies, a high MET gene copy number was observed in 38 patients (54.3%). The characteristics of the 2 groups divided according to MET gene copy number were similar. With a median follow-up duration of 26.4 months (range, 2.6-73.2 months), the estimated 3-year relapse-free survival and overall survival rates were 54.3% and 77.4%, respectively. No significant association was observed between the MET gene copy number and survival in a multivariate analysis. The MET gene copy number investigated in this study was not found to be associated with prognosis in patients with curatively resected gastric cancer.

Immunoprofile of c-MET/PI3K signaling in human salivary gland tumors

OBJECTIVE

The aim of this study was to analyze the expression pattern of proteins in the HGF/c-MET/PI3K signaling pathway in salivary gland tumors (SGTs) and to correlate the findings with the proliferative index and clinical parameters.

STUDY DESIGN

We assembled tissue microarrays (TMAs) of 108 cases of SGTs, including 69 cases of pleomorphic adenoma (PA), 24 cases of adenoid cystic carcinoma (AdCC), and 15 cases of mucoepidermoid carcinoma (MEC). An immunohistochemical analysis of hepatocyte growth factor (HGF), MET phosphorylation (p-MET), protein kinase B (AKT) phosphorylation (p-AKT), and Ki-67 proteins was performed.

RESULTS

Benign and malignant SGTs presented similar scores of HGF-positive cells (P = .36), whereas, malignant SGTs exhibited higher levels of p-MET (P = .001) and p-AKT (P = .001) than benign SGTs. No correlation of HGF, p-MET, or p-AKT expression was observed with clinical parameters. PA had a lower proliferative index than either AdCC (P = .001) or MEC (P = .001).

CONCLUSIONS

The salivary gland carcinomas exhibited increased activation of the HGF pathway, as evidenced by the phosphorylation of the MET receptor, and increased activation of the PI3K pathway, as indicated by p-AKT. These data suggest that the HGF/c-MET/PI3K signaling pathway is active in SGTs, especially in malignant neoplasms.

c-Met expression is a marker of poor prognosis in patients with locally advanced head and neck squamous cell carcinoma treated with chemoradiation

PURPOSE

To examine the prognostic significance of c-Met expression in relation to p16 and epidermal growth factor receptor (EGFR) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC) treated with definitive concurrent chemoradiation.

METHODS AND MATERIALS

Archival tissue from 107 HNSCC patients treated with chemoradiation was retrieved, and a tissue microarray was assembled. Immunohistochemical staining of c-Met, p16, and EGFR was performed. c-Met expression was correlated with p16, EGFR, clinical characteristics, and clinical endpoints including locoregional control (LRC), distant metastasis (DM), disease-free survival (DFS), and overall survival (OS).

RESULTS

Fifty-one percent of patients were positive for p16, and 53% were positive for EGFR. Both p16-negative (P≤.001) and EGFR-positive (P=.019) status predicted for worse DFS. Ninety-three percent of patients stained positive for c-Met. Patients were divided into low (0, 1, or 2+ intensity) or high (3+ intensity) c-Met expression. On univariate analysis, high c-Met expression predicted for worse LRC (hazard ratio [HR] 2.27; 95% CI, 1.08-4.77; P=.031), DM (HR 4.41; 95% CI, 1.56-12.45; P=.005), DFS (HR 3.00; 95% CI, 1.68-5.38; P<.001), and OS (HR 4.35; 95% CI, 2.13-8.88; P<.001). On multivariate analysis, after adjustment for site, T stage, smoking history, and EGFR status, only high c-Met expression (P=.011) and negative p16 status (P=.003) predicted for worse DFS. High c-Met expression was predictive of worse DFS in both EGFR-positive (P=.032) and -negative (P=.008) patients. In the p16-negative patients, those with high c-Met expression had worse DFS (P=.036) than did those with low c-Met expression. c-Met expression was not associated with any outcome in the p16-positive patients.

CONCLUSIONS

c-Met is expressed in the majority of locally advanced HNSCC cases, and high c-Met expression predicts for worse clinical outcomes. High c-Met expression predicted for worse DFS in p16-negative patients but not in p16-positive patients. c-Met predicted for worse outcome regardless of EGFR status.

MET genetic abnormalities unreliable for patient selection for therapeutic intervention in oropharyngeal squamous cell carcinoma

Background

Identification of MET genetic alteration, mutation, or amplification in oropharyngeal squamous cell carcinoma (OPSCC) could lead to development of MET selective kinase inhibitors. The aim of this study was to assess the frequency and prognostic value of MET gene mutation, amplification, and protein expression in primary OPSCC.

Methods

A retrospective chart review was conducted of patients treated for single primary OPSCC between January 2007 and December 2009. Pre-treatment OPSCC tissue samples were analyzed for MET mutations, gene amplification, and overexpression using Sanger sequencing, FISH analysis, and immunohistochemistry respectively. Univariate and multivariate analyses were used to analyze correlations between molecular abnormalities and patient survival.

Results

143 patients were included in this study. Six cases (4%) were identified that had a genetic variation, but previously described mutations such as p.Tyr1235Asp (Y1235D) or p.Tyr1230Cys (Y1230C) were not detected. There were 15 high polysomy cases, and only 3 cases met the criteria for true MET amplification, with ≥10% amplified cells per case. Immunohistochemistry evaluation showed 43% of cases were c-MET negative and in 57% c-MET was observed at the tumor cell level. Multivariate analysis showed no significant association between MET mutation, amplification, or expression and survival.

Conclusions

Our study shows a low frequency of MET mutations and amplification in this cohort of OPSCC. There was no significant correlation between MET mutations, amplification, or expression and patient survival. These results suggest that patient selection based on these MET genetic abnormalities may not be a reliable strategy for therapeutic intervention in OPSCC.

p16 status, pathologic and clinical characteristics, biomolecular signature, and long-term outcomes in head and neck squamous cell carcinomas of unknown primary

BACKGROUND

The purpose of this study was to report associations between p16 status, clinicopathologic characteristics, and outcomes for head and neck squamous cell carcinoma of unknown primary (CUP).

METHODS

Specimens of squamous cell CUP were reanalyzed. Human papillomavirus (HPV) status was determined by p16 stain. A tissue microarray (TMA) was constructed to evaluate biomarkers potentially prognostic in head and neck squamous cell carcinoma (HNSCC).

RESULTS

A majority of the population (n = 26; 74%) was p16 positive (+). Prognostic factors benefiting survival were p16+ status (p < .0001), absence of macroscopic extracapsular extension (ECE; p = .004), younger age (p = .01), and higher grade (p = 0.007). The prognostic implication of worse overall survival (OS) with macroscopic ECE (p = .009) remained significant when limited to patients who were p16+ (p = .002). Exploratory TMA between unknown primary and controls suggested a biomolecular difference between squamous cell CUP and known-primary cancer.

CONCLUSION

The majority of patients with squamous cell CUP were p16+, indicative of HPV association. P16 staining and ECE seem to be the most prognostic features in squamous cell CUP.

The Molecular Crosstalk between the MET Receptor Tyrosine Kinase and the DNA Damage Response-Biological and Clinical Aspects

Radiation therapy remains an imperative treatment modality for numerous malignancies. Enduring significant technical achievements both on the levels of treatment planning and radiation delivery have led to improvements in local control of tumor growth and reduction in healthy tissue toxicity. Nevertheless, resistance mechanisms, which presumably also involve activation of DNA damage response signaling pathways that eventually may account for loco-regional relapse and consequent tumor progression, still remain a critical problem. Accumulating data suggest that signaling via growth factor receptor tyrosine kinases, which are aberrantly expressed in many tumors, may interfere with the cytotoxic impact of ionizing radiation via the direct activation of the DNA damage response, leading eventually to so-called tumor radioresistance. The aim of this review is to overview the current known data that support a molecular crosstalk between the hepatocyte growth factor receptor tyrosine kinase MET and the DNA damage response. Apart of extending well established concepts over MET biology beyond its function as a growth factor receptor, these observations directly relate to the role of its aberrant activity in resistance to DNA damaging agents, such as ionizing radiation, which are routinely used in cancer therapy and advocate tumor sensitization towards DNA damaging agents in combination with MET targeting.

Expression of MACC1 and c-Met in human gastric cancer and its clinical significance

BACKGROUND

Recent studies have suggested that the metastasis-associated colon cancer1 (MACC1) gene can promote tumor proliferation, invasion and metastasis through an upregulation of c-Met expression. However, its role in gastric cancer is controversial. Our study investigated expression of MACC1 and c-Met in gastric cancer, as well as correlated this with clinicopathological parameters.

METHODS

Expressions of MACC1 and c-Met protein in a sample of 98 gastric carcinoma and adjacent nontumorous tissues were detected by immunohistochemistry. Their relationships and correlations with clinicopathological features were analyzed.

RESULTS

The positive rates of MACC1 and c-Met protein in primary tumors were 61.22% and 59.18%, respectively. A significant correlation was found between expression of MACC1 and c-Met (P<0.05). Expression of the MACC1 protein in gastric cancer tissue was correlated with lymph node metastasis (χ2 = 10.555,P = 0.001), peritoneal metastasis (χ2 = 5.694, P = 0.017), and hepatic metastasis (χ2 = 4.540,P = 0.033), but not with age, gender, tumor size, location, clinical stage or the distant metastases (P>0.05).

CONCLUSION

The positive rate of MACC1 protein expression was related to the protein expression of c-Met. Both had a correlation with the presence of peritoneal metastasis, lymph node metastasis and hepatic metastasis, all of which contribute to a poor prognosis for gastric cancer patients.

Targeted therapies for squamous cell carcinoma of the head and neck: current knowledge and future directions

Despite progress in the therapeutic management of patients with squamous cell carcinoma of the head and neck (SCCHN), the mortality rate of patients presenting with advanced disease remains high. One approach to improve treatment efficacy is to add novel molecular targeted agents to the classical treatment regimens. Monoclonal antibodies targeting the epidermal growth factor receptor (EGFR) have shown clinical benefits in palliative and curative settings. However, only a minority of patients presenting with recurrent or metastatic (R/M) SCCHN have meaningful tumor regression with these agents and virtually all who do develop acquired tumor resistance after a few months of treatment. For these reasons, other inhibitors of EGFR or molecules that interfere with known molecular pathways activated in SCCHN are of considerable interest, either as single agents or in combination with other treatment modalities. In this review, we discuss the different molecular therapeutic approaches explored in SCCHN. We also briefly outline new trial designs that could be used to accelerate the investigation of emerging therapeutic agents in this disease.

Measurement of calcitonin and calcitonin gene-related peptide mRNA refines the management of patients with medullary thyroid cancer and may replace calcitonin-stimulation tests

BACKGROUND

Serum calcitonin (sCT) is the main tumor marker for medullary thyroid cancer (MTC), but it has certain limitations. Various sCT assays may have important intra-assay or interassay variation and may yield different and sometimes conflicting results. A pentagastrin- or calcium-stimulation calcitonin (CT) test may be desirable in some situations. Alternatively, or in the absence of the stimulation test, mRNA detection offers the advantages of being more comfortable and less invasive; it only requires blood collection and has no side effects. The objective of this study was to investigate the applicability of measuring calcitonin-related polypeptide alpha (CALCA) gene transcripts (CT-CALCA and calcitonin gene-related peptide [CGRP]-CALCA) in patients with MTC and in relatives diagnosed with a RET mutation and to test mRNA as an alternative diagnostic tool for the calcitonin-stimulation test.

METHODS

Twenty-three healthy controls and 26 individuals evaluated for MTC were selected, including patients with sporadic or hereditary MTC and RET mutation-carrying relatives. For molecular analysis, RNA was extracted from peripheral blood, followed by cDNA synthesis using 3.5 μg of total RNA. Quantitative real-time polymerase chain reaction (RT-qPCR) was performed with SYBR Green and 200 nM of each primer for the two specific mRNA targets (CT-CALCA or CGRP-CALCA) and normalized with the ribosomal protein S8 as the reference gene.

RESULTS

We detected CALCA transcripts in the blood samples and observed a positive correlation between them (r=0.946, p<0.0001). Both mRNAs also correlated with sCT (CT-CALCA, r=0.713, p<0.0001; CGRP-CALCA, r=0.714, p<0.0001). The relative expression of CT-CALCA and CGRP-CALCA presented higher clinical sensitivity (86.67 and 100, respectively), specificity (97.06 and 97.06), positive predictive value (92.86 and 93.75), and negative predictive value (94.29 and 100), than did sCT (73.33, 82.35, 64.71, and 87.50, respectively). In addition, the CALCA transcript measurement mirrored the response to the pentagastrin test.

CONCLUSION

We demonstrate that the measurement of CALCA gene transcripts in the bloodstream is feasible and may refine the management of patients with MTC and RET mutation-carrying relatives. We propose considering the application of this diagnostic tool as an alternative to the calcitonin-stimulation test.

Expression of c-Met Is Different along the Location and Associated with Lymph Node Metastasis of Head and Neck Carcinoma

Background

Activation of the c-Met pathway is involved in cancer progression and the prognosis. We aimed to identify any association of c-Met protein expression with a number of clinicopathologic variables including infection of human papillomavirus and Epstein-Barr virus (EBV) in head and neck carcinomas (HNCa).

Methods

Eighty-two cases were enrolled in this study. Expression of c-Met and p16 was investigated immunohistochemically. EBV was detected by in situ hybridization and amplification of the c-Met gene by fluorescence in situ hybridization.

Results

The c-Met protein was expressed in 41.5% (34/82), and gene amplification was found in 1.4% (1/71). High expression of c-Met was associated with the primary location of the tumor; the hypopharynx showed the highest expression, followed by the oral cavity, larynx, and nasal cavity. Squamous cell carcinoma expressed c-Met more frequently than undifferentiated carcinoma. Also, p16 immunoreactivity or EBV infection was associated with the tumor location and well-differentiated histologic type, but were not linked to c-Met expression. The patients with positive c-Met expression showed frequent lymph node metastasis.

Conclusions

Activation of the c-Met pathway might be involved in a subset of HNCa. Cases showing positive c-Met expression should be carefully monitored because of the high probability of lymph node metastasis.

Impact of epidermal growth factor receptor, mesenchymal-epithelial transition factor, and insulin-like growth factor receptor 1 expression on survival of patients with oral and oropharyngeal cancer

The aim of this study was to evaluate the impact of expression of epidermal growth factor receptor (EGFR), mesenchymal-epithelial transition factor (c-Met), and insulin-like growth factor receptor 1 (IGF-1R) protein on response to treatment and survival in patients with oral and oropharyngeal squamous cell carcinoma (SCC). EGFR, c-Met, and IGF-1R immunohistochemical (IHC) scores were generated based on the incidence and intensity of expression of the biomarkers evaluated in paraffin-embedded sections of biopsy specimens taken before treatment from 113 patients given neoadjuvant chemoradiotherapy followed by resection for primary locally advanced oral and oropharyngeal SCC. Correlations were assessed between the IHC of the biomarkers and the patients' clinicopathological variables using Spearman's rank test. Cox's regression models were used to evaluate the impact of EGFR, c-Met, and IGF-1R, expression on survival. Almost all the patients showed expression of EGFR, c-Met, and IGF-1R (99%, 100%, and 100%, respectively). None of the biomarkers examined predicted response to neoadjuvant chemoradiotherapy or were associated with survival. In multivariate analysis, age (p=0.05), alcohol consumption (p=0.03), and pathological size/extent of the primary tumour after neoadjuvant treatment (ypT) status (p=0.009) were significantly associated with recurrence-free survival. Age (p=0.02) and alcohol consumption (p=0.02) were independently associated with overall survival. Although none of the biomarkers evaluated could be used as prognostic indicators, their common expression suggested a strong rationale for targeting EGFR, c-Met, and IGF-1R in the treatment of oral and oropharyngeal SCC.

Hepatocyte growth factor activates Wnt pathway by transcriptional activation of LEF1 to facilitate tumor invasion

Hepatocyte growth factor (HGF) is a secretory protein that plays important roles in cancer growth and metastasis. Lymphoid-enhancing factor 1 (LEF1) is a transcription factor mediating Wnt/β-catenin signaling. Using microarray analysis, we found HGF induced expression of LEF1 in liver and breast cancer cell lines. HGF induced expression of LEF1 through phosphatidylinositol 3-kinase/Akt and nuclear factor-kappa B (NF-κB) signaling. Multiple NF-κB-binding sites were mapped within 3 kb upstream of LEF1 transcription initiation site. NF-κB binding to a site 2 kb upstream of LEF1 transcription initiation site was confirmed by chromatin immunoprecipitation assay. Knockdown of LEF1 inhibited the expression of Slug and Zinc finger E-box-binding homeobox 2 (ZEB2) and markedly attenuated HGF-induced tumor migration and invasion. Using immunohistochemical staining, we found LEF1 was frequently expressed in multiple types of carcinoma but not in the non-tumorous epithelial cells. Our finding suggest that transcriptional activation of LEF1 is a mechanism of cross talk between HGF/c-Met and Wnt/β-catenin pathways and is essential for HGF-induced tumor invasion.

Protein-intrinsic and signaling network-based sources of resistance to EGFR- and ErbB family-targeted therapies in head and neck cancer

Agents targeting EGFR and related ErbB family proteins are valuable therapies for the treatment of many cancers. For some tumor types, including squamous cell carcinomas of the head and neck (SCCHN), antibodies targeting EGFR were the first protein-directed agents to show clinical benefit, and remain a standard component of clinical strategies for management of the disease. Nevertheless, many patients display either intrinsic or acquired resistance to these drugs; hence, major research goals are to better understand the underlying causes of resistance, and to develop new therapeutic strategies that boost the impact of EGFR/ErbB inhibitors. In this review, we first summarize current standard use of EGFR inhibitors in the context of SCCHN, and described new agents targeting EGFR currently moving through pre-clinical and clinical development. We then discuss how changes in other transmembrane receptors, including IGF1R, c-Met, and TGF-β, can confer resistance to EGFR-targeted inhibitors, and discuss new agents targeting these proteins. Moving downstream, we discuss critical EGFR-dependent effectors, including PLC-γ; PI3K and PTEN; SHC, GRB2, and RAS and the STAT proteins, as factors in resistance to EGFR-directed inhibitors and as alternative targets of therapeutic inhibition. We summarize alternative sources of resistance among cellular changes that target EGFR itself, through regulation of ligand availability, post-translational modification of EGFR, availability of EGFR partners for hetero-dimerization and control of EGFR intracellular trafficking for recycling versus degradation. Finally, we discuss new strategies to identify effective therapeutic combinations involving EGFR-targeted inhibitors, in the context of new system level data becoming available for analysis of individual tumors.

MET phosphorylation predicts poor outcome in small cell lung carcinoma and its inhibition blocks HGF-induced effects in MET mutant cell lines

Background:

Small cell lung carcinoma (SCLC) has poor prognosis and remains orphan from targeted therapy. MET is activated in several tumour types and may be a promising therapeutic target.

Methods:

To evaluate the role of MET in SCLC, MET gene status and protein expression were evaluated in a panel of SCLC cell lines. The MET inhibitor PHA-665752 was used to study effects of pathway inhibition in basal and hepatocyte growth factor (HGF)-stimulated conditions. Immunohistochemistry for MET and p-MET was performed in human SCLC samples and association with outcome was assessed.

Results:

In MET mutant SCLC cells, HGF induced MET phosphorylation, increased proliferation, invasiveness and clonogenic growth. PHA-665752 blocked MET phosphorylation and counteracted HGF-induced effects. In clinical samples, total MET and p-MET overexpression were detected in 54% and 43% SCLC tumours (n=77), respectively. MET phosphorylation was associated with poor median overall survival (132 days) vs p-MET negative cases (287 days)(P<0.001). Phospho-MET retained its prognostic value in a multivariate analysis.

Conclusions:

MET activation resulted in a more aggressive phenotype in MET mutant SCLC cells and its inhibition by PHA-665752 reversed this phenotype. In patients with SCLC, MET activation was associated with worse prognosis, suggesting a role in the adverse clinical behaviour in this disease.

Receptor-tyrosine-kinase-targeted therapies for head and neck cancer

Molecular therapeutics for treating epidermal growth factor receptor-(EGFR-) expressing cancers are a specific method for treating cancers compared to general cell loss with standard cytotoxic therapeutics. However, the finding that resistance to such therapy is common in clinical trials now dampens the initial enthusiasm over this targeted treatment. Yet an improved molecular understanding of other receptor tyrosine kinases known to be active in cancer has revealed a rich network of cross-talk between receptor pathways with a key finding of common downstream signaling pathways. Such cross talk may represent a key mechanism for resistance to EGFR-directed therapy. Here we review the interplay between EGFR and Met and the type 1 insulin-like growth factor receptor (IGF-1R) tyrosine kinases, as well as their contribution to anti-EGFR therapeutic resistance in the context of squamous cell cancer of the head and neck, a tumor known to be primarily driven by EGFR-related oncogenic signals.

Recently identified biomarkers that promote lymph node metastasis in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous cancer that arises in the upper aerodigestive tract. Despite advances in knowledge and treatment of this disease, the five-year survival rate after diagnosis of advanced (stage 3 and 4) HNSCC remains approximately 50%. One reason for the large degree of mortality associated with late stage HNSCC is the intrinsic ability of tumor cells to undergo locoregional invasion. Lymph nodes in the cervical region are the primary sites of metastasis for HNSCC, occurring before the formation of distant metastases. The presence of lymph node metastases is strongly associated with poor patient outcome, resulting in increased consideration being given to the development and implementation of anti-invasive strategies. In this review, we focus on select proteins that have been recently identified as promoters of lymph node metastasis in HNSCC. The discussed proteins are involved in a wide range of critical cellular functions, and offer a more comprehensive understanding of the factors involved in HNSCC metastasis while additionally providing increased options for consideration in the design of future therapeutic intervention strategies.