Aberrations of MET are associated with copy number gain of EGFR and loss of PTEN and predict poor outcome in patients with salivary gland cancer

Molecular Characteristics of Radon Associated Lung Cancer Highlights MET Alterations

Simple Summary

Lung cancer (LC) is the leading cause of cancer death worldwide. After smoking, one of the most prominent risk factors for LC development is radon (Rn) exposure. In our study we analysed and compared the genetic landscape of LC patients from a Rn exposed village with local matched non-exposed patients. Within the concordant genetic landscape, an increase in genetic MET proto-oncogene, receptor tyrosine kinase (MET) alteration in the Rn-exposed cohort was monitored, underlining the importance of routine MET testing and potential to enable a more effective treatment for this specific subgroup.

Abstract

Effective targeted treatment strategies resulted from molecular profiling of lung cancer with distinct prevalent mutation profiles in smokers and non-smokers. Although Rn is the second most important risk factor, data for Rn-dependent driver events are limited. Therefore, a Rn-exposed cohort of lung cancer patients was screened for oncogenic drivers and their survival and genetic profiles were compared with data of the average regional population. Genetic alterations were analysed in 20 Rn-exposed and 22 histologically matched non-Rn exposed LC patients using targeted Next generation sequencing (NGS) and Fluorescence In Situ Hybridization (FISH). Sufficient material and sample quality could be obtained in 14/27 non-exposed versus 17/22 Rn-exposed LC samples. Survival was analysed in comparison to a histologically and stage-matched regional non-exposed lung cancer cohort (n = 51) for hypothesis generating. Median overall survivals were 83.02 months in the Rn-exposed and 38.7 months in the non-exposed lung cancer cohort (p = 0.22). Genetic alterations of both patient cohorts were in high concordance, except for an increase in MET alterations and a decrease in TP53 mutations in the Rn-exposed patients in this small hypothesis generating study.

Case Report: Gene Heterogeneity in the Recurrent and Metastatic Lesions of a Myxoid Chondrosarcoma Patient With Aggressive Transformation

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue sarcoma. In view of the indolent course throughout the prolonged natural history of EMC, it was considered as a low-grade soft-tissue sarcoma. However, recent studies have revealed a high recurrence and metastatic potential in EMC, and the invasiveness of EMC may progress during the protracted clinical course. The mechanism for this aggressive transformation remains unknown. Here, we present a rare case of EMC with aggressive behavior. This case was confirmed via pathology and NR4A3 fluorescent in situ hybridization. To verify the genetic characteristics of this rare case, a total gene sequencing analyses was performed in the recurrent and metastatic lesions. Intriguingly, different gene mutations were determined in the recurrent and metastatic lesions, which implied the genetic heterogeneity among the different lesions might be related to the aggressiveness of EMC. Furthermore, we discuss a few potential agents against the mutated genes in this case, which may provide novel insights regarding the targeted therapy of EMC.

MET deletion is a frequent event in gastric/gastroesophageal junction/esophageal cancer: a cross-sectional analysis of gene status and signal distribution in 1,580 patients

Background

MET gene aberrations are found in several human cancers including gastric, ovarian and lung. In a large multinational cohort of patients with gastric/gastroesophageal junction/esophageal (G/GEJ/E) adenocarcinoma we assessed the MET status with respect to amplification and deletion and correlate the results with the phenotypical gene signal distribution pattern.

Methods

Tissue specimens from 1,580 patients were analyzed using a novel fluorescence in situ hybridization (FISH) assay employing a MET/CEN-7 IQFISH Probe Mix. MET amplification and deletions were defined as a MET/CEN-7 ratio ≥2.0 and a MET/CEN-7 ratio <0.8, respectively. Furthermore, the link between the MET gene status and the phenotypical signal distribution was investigated.

Results

The prevalence of MET amplification and deletions was found to be 7.2% and 8.7%, respectively. Significant differences were observed with regard to geographic regions and sex. The Asian population had the highest percentage of MET amplification (9.4%) and the lowest percentage of deletions (3.2%). MET deletions was found more frequently among males (10.1%) compared to females (5.3%) and in esophagus (17.6%) compared to the stomach (5.7%). More than 50% of the patients who harbored MET gene amplification had a heterogeneous distribution of the FISH signals. Patients with a focal signal distribution were solely to be found among the MET amplified population. MET deletion were mainly observed in the group of patients with a homogenous signal distribution.

Conclusions

The screening data from this cross-sectional study showed that MET deletion and amplification are frequent events in G/GEJ/E cancer, which are linked to different phenotypical signal distribution patterns. The role of MET deletion in relation to tumor development is not fully understood but it is likely to play a role in the oncogenic transformation of the cells.

Blockage of ETS homologous factor inhibits the proliferation and invasion of gastric cancer cells through the c-Met pathway

BACKGROUND

Gastric cancer (GC) is one of the most common and deadliest types of cancer worldwide due to its delayed diagnosis and high metastatic frequency, but its exact pathogenesis has not been fully elucidated. ETS homologous factor (EHF) is an important member of the ETS family and contributes to the pathogenesis of multiple malignant tumors. To date, whether EHF participates in the development of GC via the c-Met signaling pathway remains unclear.

AIM

To investigate the role and mechanism of EHF in the occurrence and development of GC.

METHODS

The expression of EHF mRNA in GC tissues and cell lines was measured by quantitative PCR. Western blotting was performed to determine the protein expression of EHF, c-Met, and its downstream signal molecules. The EHF expression in GC tissues was further detected by immunohistochemical staining. To investigate the role of EHF in GC oncogenesis, small interfering RNA (siRNA) against EHF was transfected into GC cells. The cell proliferation of GC cells was determined by Cell Counting Kit-8 and colony formation assays. Flow cytometry was performed following Annexin V/propidium iodide (PI) to identify apoptotic cells and PI staining to analyze the cell cycle. Cell migration and invasion were assessed by transwell assays.

RESULTS

The data showed that EHF was upregulated in GC tissues and cell lines in which increased expression of c-Met was also observed. Silencing of EHF by siRNA reduced the proliferation of GC cells. Inhibition of EHF induced significant apoptosis and cell cycle arrest in GC cells. Cell migration and invasion were significantly inhibited. EHF silencing led to c-Met downregulation and further blocked the Ras/c-Raf/extracellular signal-related kinase 1/2 (Erk1/2) pathway. Additionally, phosphatase and tensin homolog was upregulated and glycogen synthase kinase 3 beta was deactivated. Moreover, inactivation of signal transducer and activator of transcription 3 was detected following EHF inhibition, leading to inhibition of the epithelial-to-mesenchymal transition (EMT).

CONCLUSION

These results suggest that EHF plays a key role in cell proliferation, invasion, apoptosis, the cell cycle and EMT via the c-Met pathway. Therefore, EHF may serve as an antineoplastic target for the diagnosis and treatment of GC.

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.

Salivary Secretory Carcinoma With a Novel ETV6-MET Fusion: Expanding the Molecular Spectrum of a Recently Described Entity

Secretory carcinoma of the salivary glands, also known as mammary analogue secretory carcinoma, is a recently described tumor characterized by generally indolent clinical behavior and recurrent ETV6-NTRK3 fusions. However, a small subset of recent cases with high-grade histology, aggressive behavior, or alternate molecular findings are expanding the spectrum of this entity. In this case, a 59-year-old female presented with an infiltrative submandibular gland tumor that was originally classified as a high-grade acinic cell carcinoma, papillary-cystic variant. She developed persistent local disease and, 11 years after initial presentation, was found to have widespread metastases. Rereview of her primary tumor highlighted microcystic, papillary, and solid architecture, eosinophilic cytoplasm, vesicular nuclei with prominent nucleoli, abundant mitotic figures, and necrosis. Immunostains showed the tumor cells to be positive for S100 and mammaglobin and negative for DOG-1, and fluorescence in situ hybridization highlighted an ETV6 rearrangement, supporting a diagnosis of high-grade secretory carcinoma. Finally, next-generation sequencing demonstrated a novel ETV6-MET fusion. To our knowledge, this is the first ETV6-MET fusion reported in secretory carcinoma. This finding further expands the definition of secretory carcinoma while carrying implications for selecting appropriate targeted therapy.

Cooperation Between Pten and Smad4 in Murine Salivary Gland Tumor Formation and Progression

Salivary gland tumor (SGT) is a rare tumor type, which exhibits broad-spectrum phenotypic, biological, and clinical heterogeneity. Currently, the molecular mechanisms that cause SGT pathogenesis remain poorly understood. A lack of animal models that faithfully recapitulate the naturally occurring process of human SGTs has hampered research progress on this field. In this report, we developed an inducible keratin 5-driven conditional knockout mouse model to delete gene(s) of interest in murine salivary gland upon local RU486 delivery. We have deleted two major tumor suppressors, Pten, a negative regulator of the PI3K pathway, and Smad4, the central signaling mediator of TGFβ pathway, in the murine salivary gland. Our results have shown that deletion of either Pten or Smad4 in murine salivary gland resulted in pleomorphic adenomas, the most common tumor in human SGT patients. Deletion of both Pten and Smad4 in murine salivary gland developed several malignancies, with salivary adenoid cystic carcinoma (SACC) being the most frequently seen. Molecular characterization showed that SACC exhibited mTOR activation and TGFβ1 overexpression. Examination of human SGT clinical samples revealed that loss of Pten and Smad4 is common in human SACC samples, particularly in the most aggressive solid form, and is correlated with survival of SACC patients, highlighting the human relevance of the murine models. In summary, our results offer significant insight into synergistic role of Pten and Smad4 in SGT, providing a rationale for targeting mTOR and/or TGFβ signaling to control SGT formation and progression.

Concurrent MET copy number gain and KRAS mutation is a poor prognostic factor in pancreatobiliary subtype ampullary cancers

Hepatocyte growth factor (HGF) and MET are candidates of targeted therapies for cancer patients. Although MET and HGF are commonly expressed in biliary tract cancers, their expression and gene copy number status and their association with KRAS mutations have not been investigated in pancreatobiliary-type ampullary adenocarcinomas (A-ACs), one of the aggressive periampullary cancers. MET and HGF expressions and MET copy number status were examined by performing immunohistochemistry (IHC) and silver in situ hybridization (SISH) in 62 surgically resected, paraffin-embedded tumors, respectively. High MET and HGF protein expressions were detected in 24 (38.7%) and 15 (24.2%) tumors. High MET expression was associated with KRAS mutation. However, there were no associations of high MET/HGF expression alone with other clinicopathological feature or survival. MET SISH positivity was detected in 19 tumors (30.6%), where 84.2% were due to high trisomy or polysomy and only 3 cases (15.8%) were MET gene amplification. The overall MET protein overexpression was well correlated with MET SISH positivity. The concurrent MET SISH positivity and KRAS mutation, not each alone, was an independent poor prognostic factor of disease-free survival only in pancreatobiliary subtype of A-ACs, but not in intestinal subtype. Concurrent MET SISH positivity and KRAS mutation may predict a high risk of recurrence in pancreatobiliary subtype of A-ACs, indicating those markers could be potent candidates for a new therapeutic target in this cancer type. MET IHC can be used as a reliable tool screening for MET copy number status in ampullary cancers.

Genomic aberrations of MDM2, MDM4, FGFR1 and FGFR3 are associated with poor outcome in patients with salivary gland cancer

Fibroblast growth factor receptor 1 and 3 (FGFR1, FGFR3) impact on tissue homoeostasis, embryonic development and carcinogenesis. Murine double minute protein 4 (MDM4) and mouse double minute 2 homologue (MDM2) are regulators of p53-protein and may be the origin of an apoptosis overpowering cascade. A collective of 266 carcinomas of salivary glands were investigated for MDM2, MDM4, FGFR1 and FGFR3 aberrations by fluorescence in situ hybridization (FISH). The results were matched with clinicopathological parameters and with expression of PTEN and p53. MDM2 gene amplification (n = 9) and chromosomal aberrations (trisomy, n = 47; high polysomy, n = 7) are linked to high-grade malignancy (P < 0.001), lymph node metastasis (P = 0.001), advanced tumour size (P = 0.013) and stage (P < 0.001), gender (P = 0.002) and age (P = 0.001). MDM4 gene amplification (n = 19) and chromosomal aberrations (trisomy, n = 34; high polysomy, n = 31) are correlated to high-grade malignancy (P < 0.001), lymph node metastasis (P = 0.008), advanced tumour size (P = 0.039), stage (P = 0.004) and loss of PTEN (P < 0.001). Only, high-grade malignancy (P < 0.001), lymph node metastasis (P = 0.036) and advanced tumour stage (P = 0.025) are associated with FGFR3 amplification (n = 1) or chromosomal aberrations (low polysomy, n = 61; high polysomy, n = 55) but not with MDM4 alterations. FGFR1 amplifications (n = 5) and chromosomal aberrations (trisomy, n = 38; high polysomy, n = 30) are associated with high-grade malignancy (P < 0.001), advanced tumour size (P = 0.026) and stage (P = 0.004), gender (P = 0.016) and age (P = 0.023). Aberrations of MDM2, MDM4, FGFR1 and FGFR3 correlate with aggressive tumour growth and nodal metastasis. MDM2 (P < 0.001), MDM4 (P = 0.005) and FGFR3 (P = 0.006) alterations are associated with worse overall survival of patients with salivary gland cancer.

Racial and Ethnic Disparities in Salivary Gland Cancer Survival

IMPORTANCE

Several recent US studies have documented racial disparities in head and neck cancer outcomes, but few have investigated racial and ethnic differences in salivary gland cancer (SGCA) survival.

OBJECTIVE

To determine whether patient race or ethnicity affects SGCA survival.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective survival analysis of all patients with SGCA from 1988 through 2010 in the Surveillance, Epidemiology, and End Results database.

MAIN OUTCOMES AND MEASURES

Disease-specific survival according to race and ethnicity. End points assessed included age at diagnosis, sex, tumor grade, tumor size at diagnosis, extension at diagnosis, lymph node involvement at diagnosis, and treatment. Results were further analyzed by histologic subtype of SGCA.

RESULTS

Of 11,007 patients with SGCA, 1073 (9.7%) were black, and 1068 (9.7%), Hispanic. Whites' mean age at diagnosis was 63 years vs 53 and 52 years for blacks and Hispanics, respectively (P < .001). Twenty-year disease-specific survival rates for all SGCA histologic subtypes combined for whites, blacks, and Hispanics were 78%, 79%, and 81%, respectively. Unadjusted survival curves showed no significant difference between blacks and whites and an apparent advantage for Hispanics. However, multivariable Cox regression models controlling for patient, tumor, and treatment characteristics showed poorer disease-specific survival vs whites for blacks (hazard ratio [HR], 1.22 [95% CI, 1.03-1.46]; P = .03) but not for Hispanics (HR, 0.97 [0.79-1.19]; P = .77). The overall disease-specific survival disparity was due to poorer disease-specific survival for blacks vs whites with mucoepidermoid (P = .03) and squamous cell carcinomas (P = .05). Less surgical treatment for blacks than whites (57.26% vs 76.94%; P < .001) was a source of the survival disparity for squamous cell but not mucoepidermoid SGCA.

CONCLUSIONS AND RELEVANCE

Black race is a risk factor for poorer disease-specific survival for patients with mucoepidermoid or squamous cell carcinoma, whereas Hispanic ethnicity has no effect. Differing treatment between black and white patients affects survival in squamous cell but not mucoepidermoid SGCA. Differences in chemotherapy treatment, comorbidities, socioeconomic status, tumor genetic factors, and environmental exposures are potential but unproven additional sources of the racial survival disparities for mucoepidermoid and squamous cell SGCA.

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.

Analysis of 1,115 patients tested for MET amplification and therapy response in the MD Anderson Phase I Clinic

PURPOSE

This study aimed to assess MET amplification among different cancers, association with clinical factors and genetic aberrations and targeted therapy response modifications.

EXPERIMENTAL DESIGN

From May 2010 to November 2012, samples from patients with advanced tumors referred to the MD Anderson Phase I Clinic were analyzed for MET gene amplification by FISH. Patient demographic, histologic characteristics, molecular characteristics, and outcomes in phase I protocols were compared per MET amplification status.

RESULTS

Of 1,115 patients, 29 (2.6%) had MET amplification. The highest prevalence was in adrenal (2 of 13; 15%) and renal (4 of 28; 14%) tumors, followed by gastroesophageal (6%), breast (5%), and ovarian cancers (4%). MET amplification was associated with adenocarcinomas (P = 0.007), high-grade tumors (P = 0.003), more sites of metastasis, higher BRAF mutation, and PTEN loss (all P < 0.05). Median overall survival was 7.23 and 8.62 months for patients with and without a MET amplification, respectively (HR = 1.12; 95% confidence intervals, 0.83-1.85; P = 0.29). Among the 20 patients with MET amplification treated on a phase I protocol, 4 (20%) achieved a partial response with greatest response rate on agents targeting angiogenesis (3 of 6, 50%). No patient treated with a c-MET inhibitor (0 of 7) achieved an objective response.

CONCLUSION

MET amplification was detected in 2.6% of patients with solid tumors and was associated with adenocarcinomas, high-grade histology, and higher metastatic burden. Concomitant alterations in additional pathways (BRAF mutation and PTEN loss) and variable responses on targeted therapies, including c-MET inhibitors, suggest that further studies are needed to target this population.

Development and characterization of salivary adenoid cystic carcinoma cell line

OBJECTIVE

To develop in vitro adenoid cystic carcinoma cell line as a surrogate for functional studies.

MATERIALS AND METHODS

Cells obtained from a primary ACC of the base of tongue were cultivated in vitro and immortalized with h-TERT. Morphologic, cytogenetic and functional studies were performed.

RESULTS

Tumor cells were verified by positive reactions to keratin and smooth muscle actin and phenotypic cellular and nuclear features. In-vitro cell growth and colony formation assay supported their tumor nature.

CONCLUSION

We authenticated an ACC cell line with hybrid epithelial-myoepithelial feature as a resource for functional experimentation.

Copy number increase of ACTN4 is a prognostic indicator in salivary gland carcinoma

Copy number increase (CNI) of ACTN4 has been associated with poor prognosis and metastatic phenotypes in various human carcinomas. To identify a novel prognostic factor for salivary gland carcinoma, we investigated the copy number of ACTN4. We evaluated DNA copy number of ACTN4 in 58 patients with salivary gland carcinoma by using fluorescent in situ hybridization (FISH). CNI of ACTN4 was recognized in 14 of 58 patients (24.1%) with salivary gland carcinoma. The cases with CNI of ACTN4 were closely associated with histological grade (P = 0.047) and vascular invasion (P = 0.033). The patients with CNI of ACTN4 had a significantly worse prognosis than the patients with normal copy number of ACTN4 (P = 0.0005 log-rank test). Univariate analysis by the Cox proportional hazards model showed that histological grade, vascular invasion, and CNI of ACTN4 were independent risk factors for cancer death. Vascular invasion (hazard ratio [HR]: 7.46; 95% confidence interval [CI]: 1.98–28.06) and CNI of ACTN4 (HR: 3.23; 95% CI: 1.08–9.68) remained as risk factors for cancer death in multivariate analysis. Thus, CNI of ACTN4 is a novel indicator for an unfavorable outcome in patients with salivary gland carcinoma.

Overexpression of CMET is associated with signal transducer and activator of transcription 3 activation and diminished prognosis in oesophageal adenocarcinoma but not in squamous cell carcinoma

BACKGROUND

Inhibition of cMet is a promising therapeutic approach in human cancer, but few data in oesophageal cancer exist.

METHODS

Expression of mesenchymal-epithelial transition factor (cMet), epidermal growth factor receptor (EGFR) and phosphatase and tensin homologue (PTEN) were investigated immunohistochemically in 246 oesophageal carcinomas (128 adenocarcinomas (AC); 118 squamous cell carcinomas (SCC)) and corresponding metastases in a subset of AC (n=42). Data on phosphorylated signal transducer and activator of transcription 3 (pSTAT3) and HER2 expression and on lymphovascular invasion (LVI) of tumour cells were available from previous studies.

RESULTS

Overexpression of cMet was seen in 44 (34.4%) of AC, and nine (7.6%) of SCC (p<0.001, Chi square test). In AC but not in SCC, cMet expression correlated with EGFR expression (p<0.001, Chi square test), pSTAT3 expression (p=0.01, Chi square tests) and LVI of tumour cells (p<0.001, Chi square test). Overexpression of cMet was associated with shorter disease free, disease specific and overall survival of AC patients (p<0.05, Cox regression, respectively). All cMet positive ACs in which metastases were investigated had also cMet positive lymph node and distant metastases, but 25% of cMet negative primary tumours showed cMet positive lymph node and 33% distant metastases.

CONCLUSIONS

CMet plays no relevant role in most oesophageal SCC. In contrast, cMet overexpression seems to be a key oncogene in about 35% of oesophageal AC, representing a highly promising therapeutic target and prognostic factor.

PTEN deletions are related to disease progression and unfavourable prognosis in early bladder cancer

AIMS

This study aimed to determine the prevalence and clinical significance of deletions of the tumour suppressor gene PTEN in bladder cancer.

METHODS AND RESULTS

A tissue microarray with 686 bladder cancers was analysed for PTEN deletions by fluorescence in-situ hybridization. PTEN mutations were analysed in nine tumours with heterozygous PTEN deletion. Heterozygous PTEN deletions were present in 16.5% of tumours and were associated with grade (P = 0.0024) and p53 status (P = 0.0141), but not linked to stage (P = 0.0965). PTEN deletions were seen in 5.8% of pTaG1, 10.9% of pTaG2, 29.0% of pTaG3, 16.7% of pT1G2, 22.2% of pT1G3, 17.7% of pT2-4G2 and 20.9% of pT2-4G3 tumours (P = 0.0235). PTEN deletions were associated significantly with recurrences in pTa tumours (P = 0.0173), progression in pT1 tumours (P = 0.0016), but not with overall or cancer-specific survival in pT2 tumours. Multivariate analyses including grade and PTEN deletions revealed that PTEN deletions but not grade were associated independently with recurrence in pTa tumours (P = 0.0377) and progression in pT1 tumours (P = 0.0030). No inactivating PTEN mutations were found.

CONCLUSIONS

PTEN is linked to aggressive tumour phenotype and to unfavourable outcome in early bladder cancer. Heterozygous PTEN loss, i.e. reduced PTEN gene dosage, might be sufficient to cause aggressive tumour behaviour in bladder cancer cells.

Predictors of cervical lymph node metastasis in salivary gland cancer

BACKGROUND

This study compares clinicopathological parameters with novel molecular markers for predicting cervical lymph node metastasis in salivary gland cancer.

METHODS

Three hundred sixteen salivary gland carcinomas were included in this study. Genomic epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), phosphatase and tensin homolog (PTEN), and hepatocyte growth factor receptor (MET) was determined by fluorescence in situ hybridization (FISH). Chi-square tests, multivariate regression, and Kaplan-Meier survival analysis were used for statistics.

RESULTS

Nodal staging determines long-term survival. Clinicopathological parameters associated with positive neck nodes are advanced age (p = .006), T3/T4 classification, histological high-grade malignancy, and diagnosis of salivary duct carcinoma (p < .001 each). Neck node metastases also correlate with copy number gain of EGFR (p = .004) and HER2, aberration of MET, and deletion of PTEN (p < .001 each). Multivariate analysis showed SDC (p = .002) to be the strongest predictor of lymph node metastasis, followed by MET aberration (p = .009), T3/T4 classification (p = .017), PTEN deletion (p = .042), and adenocarcinoma not otherwise specified (NOS; p = .047).

CONCLUSION

The histological subtype is crucial for decisions regarding neck dissection. New molecular parameters may also indicate elective treatment of the neck.