Loss of PTEN is associated with elevated EGFR and HER2 expression and worse prognosis in salivary gland cancer

Genetic Rearrangements in Different Salivary Gland Tumors: A Systematic Review

Salivary gland tumors (SGT) encompass a wide range of neoplasms, each with its own unique histological type and clinical presentation. This review hones in on prevalent subtypes of SGTs, including adenoid cystic carcinoma (ACC), salivary duct carcinoma (SDC), and polymorphous adenocarcinoma (PAC). The articles, identified through specific keywords, were meticulously screened in databases like PubMed, Scopus, Google Scholar, and Web of Science from 2018 to 2023. Eight articles delved into genetic modifications among the selected SGT types. A fusion protein known as MYB-NF1B is typically associated with ACC, promoting cell proliferation while inhibiting apoptosis. The presence of MYB modifications in ACCs is a beacon of hope, as it is linked to a more favorable prognosis. In contrast, SDCs often exhibit HER2 expression. The invasive nature of SGTs contributes to their resistance to treatment. In the case of PAC, the role of PRKD1 is particularly noteworthy. PRKD1, integrated with other genes from the PRKD1/2/3 cluster, helps to differentiate PAC from other diseases. Furthermore, the genetic profiles of KTN1-PRKD1) and PPP2R2A:PRKD1 are distinct. The significant genetic variability among SGTs necessitates meticulous examination. This field is in a constant state of evolution, with new discoveries reshaping our understanding. Genetics is a key player in deciphering SGTs and tailoring treatments. This complex neoplasm demands ongoing research to uncover all genetic influences, thereby enhancing diagnostic methodologies, therapeutic strategies, and patient outcomes.

Molecular Aspects of Mucoepidermoid Carcinoma and Adenoid Cystic Carcinoma of the Salivary Gland

BACKGROUND

Salivary gland tumors (SGTs) are rare and highly heterogeneous lesions, making diagnosis a challenging activity. In addition, the small number of studies and samples evaluated difficults the determination of prognosis and diagnosis. Despite the solid advances achieved by research, there is still an intense need to investigate biomarkers for diagnosis, prognosis and that explain the evolution and progression of SGTs.

METHODS

We performed a comprehensive literature review of the molecular alterations focusing on the most frequent malignant SGTs: mucoepidermoid carcinoma and adenoid cystic carcinoma.

RESULTS

Due to the importance of biomarkers in the tumorigenenic process, this review aimed to address the mechanisms involved and to describe molecular and biomarker pathways to better understand some aspects of the pathophysiology of salivary gland tumorigenesis.

CONCLUSIONS

Molecular analysis is essential not only to improve the diagnosis and prognosis of the tumors but also to identify novel driver pathways in the precision medicine scenario.

ERBB2 Amplification and HER2 Expression in Salivary Duct Carcinoma: Evaluation of Scoring Guidelines and Potential for Expanded Anti-HER2 Therapy

Salivary duct carcinoma (SDC) is aggressive with limited therapeutic options. A subset of SDC display human epidermal growth factor receptor 2 (HER2) protein overexpression by immunohistochemistry, and some show ERBB2 gene amplification. Guidelines for HER2 scoring are not firmly established. Recent advances in breast carcinoma have established a role for anti-HER2 therapies in lesions with low HER2 expression lacking ERBB2 amplification. Delineating HER2 staining patterns in SDC is critical for evaluating anti-HER2 treatments. In total, 53 cases of SDC resected at our institution between 2004 and 2020 were identified. Androgen receptor (AR) and HER2 immunohistochemistry and ERBB2 fluorescence in situ hybridization were performed in all cases. AR expression was scored for percentage positive cells and categorized as positive (>10% of cells), low positive (1%-10%), or negative (<1%). HER2 staining levels and patterns were recorded, scored using 2018 ASCO/CAP guidelines, and categorized into HER2-positive (3+ or 2+ with ERBB2 amplification), HER2-low (1+ or 2+ without ERBB2 amplification), HER2-very low (faint staining in <10% of cells), or HER2-absent types. Clinical parameters and vital status were recorded. Median age was 70 years, with a male predominance. ERBB2-amplified tumors (11/53; 20.8%) presented at lower pT stages (pTis/pT1/pT2; P = .005, Fisher exact test) and more frequently had perineural invasion (P = .007, Fisher exact test) compared with ERBB2 nonamplified tumors; no other pathologic features differed significantly by gene amplification status. In addition, 2+ HER2 staining by 2018 ASCO/CAP criteria was most common (26/53; 49%); only 4 cases (8%) were HER2-absent status; 3+ HER2 staining was found in 9 tumors, and all were ERBB2 amplified. Six patients with HER2-expressing tumors received trastuzumab therapy, including 2 with ERBB2-amplified tumors. Overall survival and recurrence-free survival did not differ significantly based on ERBB2 status. This work suggests that 2018 ASCO/CAP guidelines for HER2 evaluation in breast carcinoma could be applied to SDC. Our findings also show broad overexpression of HER2 in SDC raising the possibility that more patients may benefit from anti-HER2-directed therapies.

Molecularly guided treatment of metastatic parotid gland carcinoma in adults

Background

Advanced therapy-refractory parotid gland carcinomas have a poor prognosis with limited therapy options. We used molecular profiling to offer molecular guided therapies to patients with advanced metastatic parotid gland malignancies.

Methods

In this retrospective analysis we describe the molecular profiling of ten patients diagnosed with therapy-refractory metastatic parotid gland malignancies.

Results

We identified seven genetic aberrations in five patients: two mutations in CDKN2A and one mutation in APC, ATM, TP53, SMARCB1 and FGFR1, respectively. No mutations were detected in five patients. The IHC demonstrated frequent expressions of EGFR and p‑mTOR, as well as PTEN in eight patients. For four fifths (n = 8) of the patients, a targeted therapy was suggested. Eventually, three patients received the targeted therapy recommendation and one patient achieved stable disease for 14 months.

Conclusion

A total of eight therapy recommendations were provided. Based on our observations, molecular-guided therapies may be a feasible treatment approach for this rare disease entity.

Prognostic and clinical implications of c-erbB-2 expression in patients with oral cancer: A meta-analysis

BACKGROUND

Recently, many studies have suggested that the aberrant expression of c-erbB-2 existed in oral cancer (OC) patients and had a correlation with poor clinical features across OC patients. Considering the inconsistent results among published articles, we performed the meta-analysis to assess the prognostic and clinical effect of c-erbB-2 expression on oral tumors.

METHODS

Web of Science, Embase, and PubMed were retrieved to acquire relevant publications based on selection criteria, up to February 8, 2020. Pooled odds ratios (OR) and hazard ratios (HR) with 95% confidence intervals (CI) were applied to evaluate the associations between c-erbB-2 expression and overall survival (OS), disease specific survival, disease-free survival as well as clinicopathology of OC.

RESULTS

A total of 30 literatures with 1499 patients for survival of OC were enrolled in this meta-analysis. The results indicated that c-erbB-2 overexpression was significantly associated with poor OS (HR = 2.40, 95% CI = 1.53-2.55, P < .05), disease specific survival (HR = 2.60, 95% CI = 1.11-4.10, P < .05) and disease-free survival (HR = 2.22, 95% CI = 1.46-2.99, P < .05). Subgroup analysis based on race showed that the significant prognostic value of c-erbB-2 in OC was found both in Caucasians and Asians (OS of Caucasians, HR = 2.90, 95% CI = 1.50-4.31, P < .05; OS of Asians, HR = 1.90, 95% CI = 1.27-2.53, P < .05). Moreover, OC patients with enhanced c-erbB-2 expression were prone to male (OR = 1.97, 95% CI = 1.22-3.19, P < .05), advanced TNM stage (OR = 1.84, 95% CI = 1.17-2.88, P < .05), lymph node metastasis (OR = 2.23, 95% CI = 1.47-3.36, P < .05) and advanced grade (OR = 1.98, 95% CI = 1.30-3.01, P < .05), but not associated with distant metastasis (OR = 1.65, 95% CI = 0.98-3.04, P > .05).

CONCLUSIONS

c-erbB-2 may be a potential indicator in the prediction of prognosis and clinicopathological features in OC patients.

PTEN downregulates WD repeat‑containing protein 66 in salivary adenoid cystic carcinoma

Salivary adenoid cystic carcinoma (SACC) is one of the most common types of salivary gland cancer that causes substantial morbidity and mortality. Despite the substantial health burden of SACC, the molecular mechanisms underlying its development and progression remain poorly understood. We previously reported the loss of phosphatase and tensin homolog (PTEN) expression to be common among SACC tumors, and the PTEN deficiency to be correlated with enrichment of epithelial-mesenchymal transition (EMT) genes based on expression array analysis. The aim of the present study was to investigate further the functional function of WD repeat-containing protein 66 (WDR66), one of the enriched EMT genes, in the context of PTEN deficiency and SACC pathogenesis. WDR66 was identified to be required to maintain the EMT phenotype and the expression of cancer stem cell genes in the context of PTEN deficiency. Furthermore, knockdown of WDR66 decreased cellular proliferation, migration and invasion. Finally, WDR66 expression was identified to be inversely associated with PTEN expression and negatively correlated with the overall survival of patients with SACC. Collectively, the results of the present study revealed a novel function of WDR66 in mediating the progression of PTEN-deficient SACCs, thereby suggesting WDR66 inhibition to be a potential therapeutic approach towards successful management of SACC disease progression, particularly against tumors with decreased PTEN expression levels.

Expression of PTEN, Androgen Receptor, HER2/neu, Cytokeratin 5/6, Estrogen Receptor-Beta, HMGA2, and PLAG1 in Salivary Duct Carcinoma

Salivary duct carcinoma (SDC) is an aggressive neoplasm that resembles high-grade invasive ductal carcinoma of the breast. It can develop de novo or from the malignant transformation of pleomorphic adenoma (PA). We performed immunohistochemical stains for phosphatase and tensin homologue [PTEN androgen receptor (AR)], HER2/neu, cytokeratin 5/6, estrogen receptor-beta, high-mobility group AT-hook 2 (HMGA2), and pleomorphic adenoma gene 1 (PLAG1) on tissue microarray samples of 75 SDCs and 31 adenocarcinomas, not otherwise specified (NOS). Our data showed the following in SDC samples: loss of PTEN was found in 17 of 60 (28.3%); AR was expressed in 43 of 62 (69.4%); HER2/neu was overexpressed in 25 of 58 (43.1%); cytokeratin 5/6 was expressed in 14 of 54 (25.9%); estrogen receptor-beta was expressed in 37 of 56 (66.1%); HMGA2 was expressed in 29 of 63 (46.0%); and PLAG1 was expressed in 0 of 62 (0%). In addition, there was no statistically significant difference in the age at onset between patients with HMGA2-positive SDCs (range 32-85 years; mean: 64.3 years; median: 64.5 years) and those with HMGA2-negative SDCs (range 41-79 years; mean: 62.5 years; median: 64.5 years). There was also no statistically significant difference in overall survival between patients with HMGA2-positive and HMGA2-negative SDCs (follow-up period range 3-201 months; mean: 49.8 months; median: 30 months). Among 10 patients with a definite PA component (SDC ex-PA), 6 were positive and 4 were negative for HMGA2. Our data were consistent with previous findings that AR and estrogen receptor-beta are expressed in most SDCs, whereas HER2/neu overexpression and loss of PTEN are expressed in a subset of SDCs. In our cohort of patients, HMGA2 was expressed in approximately half of SDCs. HMGA2 and PTEN are promising therapeutic targets for salivary gland tumors.

Frequent PTEN loss and differential HER2/PI3K signaling pathway alterations in salivary duct carcinoma: Implications for targeted therapy

BACKGROUND

Patients with advanced primary and recurrent salivary duct carcinoma (SDC), a rare and lethal malignancy, have limited therapeutic options. Novel small-molecule agents aimed at targeting critical signaling associated with SDC tumorigenesis may lead to new therapeutic options for patients with these tumors. The human epidermal growth factor receptor 2 (HER2)/phosphoinositide 3-kinase (PI3K) axis, an important oncogenic pathway, has been targeted for therapy in several solid tumors. Currently, little is known about the role and clinical implications of alterations of the HER2/PI3K pathway in patients with SDC.

METHODS

The authors investigated the clinicopathologic features, genetic alterations, and expression of key members of the HER2/PI3K pathway in 43 primary tumors and conducted in vitro functional and targeted drug-response analyses on cell lines derived from salivary epithelial carcinomas.

RESULTS

In primary tumors, loss of phosphatase and tensin homolog (PTEN) expression was identified in 22 of 43 tumors (51%), overexpression of HER2 was observed in 12 of 43 tumors (28%), and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) mutations were identified in 12 of 43 tumors (28%). Phosphorylated protein kinase B (p-AKT) was highly expressed in most tumors. Most tumors (70%) displayed mutually exclusive alterations of PI3K members, whereas 8 tumors (19%) had 2 or more concurrent abnormalities. In vitro studies demonstrated a direct association between PTEN loss and PI3K pathway activation and evidence of response to combined PI3Kα and PI3Kβ and/or pan-PI3K inhibitors.

CONCLUSIONS

The current analyses reveal frequent PTEN loss and mutually exclusive alterations of key PI3K pathway members in SDC and demonstrate in vitro evidence of a response to pan-PI3K inhibitors. These results provide a framework for a biomarker-based substratification of patients with SDC in future targeted therapy. Cancer 2018;124:3523-32. © 2018 American Cancer Society.

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.

Predictive value of EGFR-PI3K-pAKT-mTOR-pS6 pathway in sinonasal squamous cell carcinomas

BACKGROUND AND OBJECTIVES

We have previously indicated that EGFR has a role in carcinogenesis in a subgroup of sinonasal squamous cell carcinomas (SNSCC). In addition, EGFR activates 2 of the most important intracellular signalling pathways: PI3K/pAKT/mTOR/pS6 and MAP pathway kinases. The objective of this study was to evaluate the involvement of the EGFR/PI3K/pAKT/mTOR/pS6 pathway and its relationship with clinical-pathological parameters and follow-up of sinonasal squamous cell carcinoma.

MATERIAL AND METHODS

The immunohistochemical expression of different components of the PI3K/AKT/mTOR/pS6 pathway and its relationship with various clinical-pathological parameters was studied in a series of 54 patients with SNSCC.

RESULTS

Loss of PTEN expression was observed in 33/54 cases (61%) and pAKT, mTOR and pS6 pre-expression was observed in 19/54 cases (35%), 8/54 cases (15%), and 47/54 cases (87%), respectively. Loss of PTEN expression was related to intracranial invasion and development of regional metastases (p=0.005). Overexpression of pS6 was associated with a decrease in survival (p=0.008), presence of local recurrences (p=0.055), and worsening of overall prognosis (p=0.007). No significant relationships were observed between pAKT and mTOR expression and the clinicopathological parameters studied.

CONCLUSIONS

Alterations in the expression of EGFR/PI3K/pAKT/mTOR/pS6 pathway components are common in a subgroup of SNSCC. This study reveals that the absence of pS6 overexpression is associated with better clinical outcomes. Therefore, pS6 expression could be considered as an unfavourable prognostic marker.

Single nucleotide polymorphisms rs701848 and rs2735343 in PTEN increases cancer risks in an Asian population

We performed this meta-analysis to analyze the cancer risk to individuals carrying the rs701848 and rs2735343 single nucleotide polymorphisms (SNPs) in the phosphatase and tensin homolog (PTEN) gene. We searched the PubMed, EMBASE, Cochrane library and the national knowledge infrastructure of China (CNKI) databases and identified 18 eligible case-control studies with 5458 cases and 6003 controls for rs701848 as well as 5490 cases and 6209 controls for rs2735343. Our analyses demonstrated that cancer risk was associated with rs701848 in the recessive model (CC vs. CT+TT, OR=1.169, 95% CI: 1.061-1.288) and with rs2735343 in the dominant model (GC+CC vs. GG, OR=0.758, 95% CI: 0.590-0.972). Subgroup analysis showed that in Asian subjects, carrying the C allele of rs701848 or GG genotype of rs2735343 was associated with increased cancer risk. Moreover, Asian subjects carrying the TC/CC genotype or C allele of rs701848 were associated with increased risk of esophageal squamous cell cancer. This meta-analysis indicates that the PTEN rs701848 (CC) and rs2735343 (GG) polymorphisms are associated with increased cancer risk in Asian subjects.

Somatic mutations in salivary duct carcinoma and potential therapeutic targets

Background

Salivary duct carcinomas (SDCa) are rare highly aggressive malignancies. Most patients die from distant metastatic disease within three years of diagnosis. There are limited therapeutic options for disseminated disease.

Results

11 cases showed androgen receptor expression and 6 cases showed HER2 amplification. 6 Somatic mutations with additional available targeted therapies were identified: EGFR (p.G721A: Gefitinib), PDGFRA (p.H845Y: Imatinib and Crenolanib), PIK3CA (p.H1047R: Everolimus), ERBB2 (p.V842I: Lapatinib), HRAS (p.Q61R: Selumetinib) and KIT (p.T670I: Sorafenib). Furthermore, alterations in PTEN, PIK3CA and HRAS that alter response to androgen deprivation therapy and HER2 inhibition were also seen.

Materials and Methods

Somatic mutation analysis was performed on DNA extracted from 15 archival cases of SDCa using the targeted Illumina TruSeq Amplicon Cancer Panel. Potential targetable genetic alterations were identified using extensive literature and international somatic mutation database (COSMIC, KEGG) search. Immunohistochemistry for androgen receptor and immunohistochemistry and fluorescent in situ hybridization for HER2 were also performed.

Conclusions

SDCa show multiple somatic mutations, some that are amenable to pharmacologic manipulation and others that confer resistance to treatments currently under investigation. These findings emphasize the need to develop testing and treatment strategies for SDCa.

Lacrimal gland ductal carcinomas: Clinical, Morphological and Genetic characterization and implications for targeted treatment

PURPOSE

Ductal carcinomas (DCs) of the lacrimal gland are very rare but aggressive malignancies. We investigated DC of the lacrimal gland for potentially clinically actionable targets in the search for new therapeutic options.

METHODS

Case 1: A 77-year-old man, presented with diplopia and xerophtalmia; case 2: A 53-year-old man, presented with headache, proptosis and chemosis and case 3: A 73-year-old man, presenting with chemosis and a corneal abscess. All three cases were characterized morphologically including immunohistochemistry and genetically with fluorescence in situ hybridization (FISH) and one case with next-generation sequencing (NGS) of cancer relevant genes.

RESULTS

Cases 1 and 3 were composed of large, rounded, irregular cystic nodules of carcinoma cells with prominent central comedonecrosis, whereas case 2 had a scirrhous morphology. High expression of CK7, CK19, EMA, p53 and HER2 was characteristic for all three tumours. Androgen receptor was intensely positive in case 1, in scattered cells in case 2 and negative in case 3, whereas oestrogen and progesterone receptor were consistently negative. Genetically, a hemizygous deletion and a point mutation in PTEN were identified in case 1, whereas HER2 amplification was found in cases 2 and 3.

CONCLUSION

This study identified a spectrum of genetic events and pattern of protein expression in DC of the lacrimal gland similar to a subset of carcinomas of the breast and ductal carcinomas of the salivary glands. For therapeutic purposes, aberrations in several components of especially the HER2 signalling pathway could alleviate the effect of HER2-directed therapy illustrating an inadequacy of isolated HER2 testing.

New Developments in Salivary Gland Pathology: Clinically Useful Ancillary Testing and New Potentially Targetable Molecular Alterations

Accurate diagnosis of salivary gland tumors can be challenging because of the many diagnostic entities, the sometimes extensive morphologic overlap, and the rarity of most tumor types. Ancillary testing is beginning to ameliorate some of these challenges through access to newer immunohistochemical stains and fluorescence in situ hybridization probes, which can limit differential diagnostic considerations in some cases. These ancillary testing strategies are especially useful in small biopsy samples, including aspiration cytology. Molecular techniques are also expanding our understanding of salivary gland tumor pathology and are helping to identify potential targets that may improve treatment for some of these tumors. Here, we summarize the clinical use of new immunohistochemical markers in our practice and review the current understanding of chromosomal rearrangements in salivary gland tumor pathology, emphasizing the prospects for exploiting molecular alterations in salivary gland tumors for diagnosis and targeted therapy. We find that immunohistochemistry and fluorescence in situ hybridization are powerful tools toward the diagnosis of salivary gland tumors, especially when used in a systematic manner based on morphologic differential-diagnostic considerations. As new targeted therapies emerge, it will become increasingly vital to incorporate appropriate molecular testing into the pathologic evaluation of salivary gland cancers.

Expression, Mutation, and Amplification Status of EGFR and Its Correlation with Five miRNAs in Salivary Gland Tumours

Malignant salivary gland tumours are rare histologically and clinically heterogeneous group of tumours, missing prognostic factors and therapeutic targets. MicroRNAs (miRNAs), small noncoding RNAs, and posttranscriptional regulators of mRNA are poorly described in different subtypes of salivary gland tumours. Epidermal growth factor receptor (EGFR), an important therapeutic target and target of certain miRNAs (i.e., miR-133b), shows variable degrees of expression in salivary gland tumours. Our study included 70 parotid gland tumours of different histological subtypes. Expression, mutations, and copy number variations (CNVs) of EGFR were determined using immunohistochemistry, single-stranded conformation polymorphism, quantitative polymerase chain reaction (qPCR), and fluorescence in situ hybridization. Expression of miR-99b, miR-133b, miR-140, miR-140-3p, and let-7a was analysed using qPCR. Expression of EGFR was observed in 37% of tumours with low and 40% of tumours with high malignant potential. There were no mutations, with the majority of samples showing polysomy of chromosome 7. Based on histological subtypes, we found differential expression of all five miRNAs. We confirmed association of reactivity of EGFR, miR-133b, miR-140, miR-140-3p, and let-7a with CNV of EGFR and a positive association between miR-133b/let-7a and reactivity of EGFR. Age and need for postoperative radiotherapy were characterized as significant in multivariate survival analysis.

Sustained response of HER2-positive metastatic salivary adenocarcinoma, not otherwise specified, treated with trastuzumab

OBJECTIVE

Adenocarcinoma-not otherwise specified (AD-NOS) is an aggressive salivary gland carcinoma subtype with poor prognosis. Her2/neu-targeted therapy may be beneficial in cases of overexpression (20% of AD-NOS). Here, a case of metastatic AD-NOS of the submandibular gland showing sustained complete response to trastuzumab is reported, and the existing literature is reviewed.

STUDY DESIGN AND RESULTS

A 68-year-old male with poorly differentiated AD-NOS of the submandibular gland with multiple metastases (T3 N2 bM1) underwent radical surgery and adjuvant radiation. The primary lesion demonstrated Her2/neu overexpression, and treatment with trastuzumab was initiated. The patient remains alive without evidence of disease at 36-months after treatment (three cycles of trastuzumab). Literature review of all published trastuzumab-based therapy studies (1990-2015) for salivary gland carcinoma is included.

CONCLUSIONS

Definitive clinical trials of trastuzumab-based interventions are challenging to undertake in rare tumors. This report adds to increasing evidence for trastuzumab-based therapy in salivary carcinomas, where sustained partial response at 36-months is achievable.

High frequency of loss of PTEN expression in human solid salivary adenoid cystic carcinoma and its implication for targeted therapy

Salivary gland tumor (SGT) is one of the least studied cancers due to its rarity and heterogeneous histological types. Here, we reported that loss of PTEN expression was most frequently found in the poorly differentiated, high grade solid adenoid cystic carcinomas. Loss of PTEN expression correlated with activation of mTOR by increased phosphorylated S6 ribosome protein. We further functionally studied the role of PTEN in a pair of human SACC cell lines, SACC-83 and SACC-LM. Reduced PTEN level was correlated with the metastasis potential. When we knocked down PTEN in the SACC-83 cell line, we observed increased proliferation and enhanced migration/invasion in vitro, and increased tumor size in vivo. We further tested the therapeutical effect by applying a PI3K/mTOR inhibitor NVP-BEZ235 to both SACC cell lines. Decreased cell proliferation, increased apoptosis, as well as reduced cell migration/invasion were observed in both cell lines upon the NVP-BEZ235 treatment. Moreover, the NVP-BEZ235 treatment in a SGT xenograft mouse model significantly reduced primary tumor size and lung metastasis. Taken together, our results demonstrated that PTEN is a potent tumor suppressor in human SGTs, and targeting PI3K/mTOR pathway may be effective in the targeted therapy for human SGT patients with loss of PTEN expression.

Genetic alterations in salivary gland cancers

Salivary gland cancers are an incredibly heterogeneous group of tumors that include 24 histologically distinct tumor types. The use of new genetic methods has paved the way for promising advancements in our understanding of the molecular biology underlying each type of tumor. The objective of this review was to highlight common oncogenes, tumor suppressor genes, and cytogenetic and epigenetic changes associated with the most common tumor types: mucoepidermoid carcinoma, adenoid cystic carcinoma, salivary duct carcinoma, mammary analogue secretory carcinoma, hyalinizing clear cell carcinoma, carcinoma ex pleomorphic adenoma, and acinic cell carcinoma. Recent insights into the pathogenesis of each cancer subtype have helped better define and classify these tumors. Further research in salivary gland cancers should focus on determining the key genes involved in the tumorigenesis of each distinct malignancy and identifying individualized chemotherapies directed at these targets. Cancer 2016;122:1822-31. © 2016 American Cancer Society.

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.

Molecular characterization of apocrine salivary duct carcinoma

Contemporary classification and treatment of salivary duct carcinoma (SDC) require its thorough molecular characterization. Thirty apocrine SDCs were analyzed by the Ion Ampliseq Cancer HotSpot panel v2 for mutations in 50 cancer-related genes. Mutational findings were corroborated by immunohistochemistry (eg, TP53, BRAF, β-catenin, estrogen, and androgen receptors) or Sanger sequencing/SNaPshot polymerase chain reaction. ERBB2 (HER2), PTEN, FGFR1, CDKN2A/P16, CMET, EGFR, MDM2, and PIK3CA copy number changes were studied by fluorescence in situ hybridization. TP53 mutations (15/27, 56%), PTEN loss (11/29, 38%, including 2 cases with PTEN mutation), PIK3CA hotspot mutations (10/30, 33%), HRAS hotspot mutations (10/29; 34%), and ERBB2 amplification (9/29, 31%, including 1 case with mutation) represented the 5 most common abnormalities. There was no correlation between genetic changes and clinicopathologic parameters. There was substantial overlap between genetic changes: 8 of 9 cases with ERBB2 amplification also harbored a PIK3CA, HRAS, and TP53 mutation and/or PTEN loss. Six of 10 cases with PIK3CA mutation also had an HRAS mutation. These findings provide a molecular rationale for dual targeting of mitogen-activated protein kinase and phosphoinositide 3-kinase pathways in SDC. FGFR1 amplification (3/29, 10%) represents a new potential target. On the basis of studies of breast carcinomas, the efficacy of anti-ERBB2 therapy will likely be decreased in SDC with ERBB2 amplification co-occurring with PIK3CA mutation or PTEN loss. Therefore, isolated ERBB2 testing is insufficient for theranostic stratification of apocrine SDC. On the basis of the prevalence and type of genetic changes, apocrine SDC appears to resemble one subtype of breast carcinoma-"luminal androgen receptor positive/molecular apocrine."

Expression and clinical evidence of miR-494 and PTEN in non-small cell lung cancer

The aim of this study was to explore the expression and clinical significance of miR-494 and PTEN (phosphatase and tensin homologue deleted on chromosome ten) in non-small cell lung cancer (NSCLC). Immunohistochemistry for PTEN and in situ hybridization (ISH) for miR-494 were performed in 92 NSCLC tissues and 10 normal lung tissues to detect their expression, and correlation between their expression with clinical characteristics and prognosis was analyzed. The expression of miR-494 was significantly higher in NSCLC than in normal lung tissues (P = 0.004). The positive expression of PTEN protein in the lung carcinoma tissues was significantly lower than that in the normal lung tissues (P = 0.013), while the level of miR-494 expression was negatively correlated with PTEN expression (r = -0.577, P < 0.01). The high positive rate of miR-494 was positively correlated with pathological TNM (p-TNM) staging and lymph node metastasis. The expression of miR-494 was negatively correlated with grade of differentiation. However, the expression of PTEN was positively correlated with grade of differentiation. Patients with over-expression of miR-494 had a shorter overall survival (OS), while the negative group of PTEN was correlated with poor OS. MiR-494 over-expression and low PTEN expression are closely related to tumor p-TNM staging and lymph node metastasis, differentiation, and OS. Combined detection of PTEN and miR-494 can aid in determining malignancy degree and the prognosis of patients with NSCLC. MiR-494 may be served as a novel prognostic factor and may lead to new treatment strategies for NSCLC.

Somatic copy number alterations associated with Japanese or endometriosis in ovarian clear cell adenocarcinoma

When compared with other epithelial ovarian cancers, the clinical characteristics of ovarian clear cell adenocarcinoma (CCC) include 1) a higher incidence among Japanese, 2) an association with endometriosis, 3) poor prognosis in advanced stages, and 4) a higher incidence of thrombosis as a complication. We used high resolution comparative genomic hybridization (CGH) to identify somatic copy number alterations (SCNAs) associated with each of these clinical characteristics of CCC. The Human Genome CGH 244A Oligo Microarray was used to examine 144 samples obtained from 120 Japanese, 15 Korean, and nine German patients with CCC. The entire 8q chromosome (minimum corrected p-value: q = 0.0001) and chromosome 20q13.2 including the ZNF217 locus (q = 0.0078) were amplified significantly more in Japanese than in Korean or German samples. This copy number amplification of the ZNF217 gene was confirmed by quantitative real-time polymerase chain reaction (Q-PCR). ZNF217 RNA levels were also higher in Japanese tumor samples than in non-Japanese samples (P = 0.027). Moreover, endometriosis was associated with amplification of EGFR gene (q = 0.047), which was again confirmed by Q-PCR and correlated with EGFR RNA expression. However, no SCNAs were significantly associated with prognosis or thrombosis. These results indicated that there may be an association between CCC and ZNF217 amplification among Japanese patients as well as between endometriosis and EGFR gene amplifications.

Human Epidermal Growth Factor Receptor 2 (HER2/neu) in Salivary Gland Carcinomas: A Review of Literature

The aim of our study is to assess the relation of human epidermal growth factor receptor 2 or HER2/neu with the development of salivary gland carcinomas and use of Herceptin in the treatment of these cancers. A literature search was conducted using MEDLINE accessed via the National Library of Medicine PubMed interface searching for articles from 1994 up to 2014 relating to the existence of HER-2 protein and gene in salivary gland carcinomas and HER2/neu targeted therapy, written in English language. Almost all the studies in literature reported a frequent over expression and amplification of HER2/nue in salivary duct carcinomas (SDC) compared to other salivary gland cancers. Herceptin given as a monotherapy was not effective. The data on Herceptin combined chemotherapy are potentially promising but inadequate to evaluate drug activity, as patients also received a variety of cytotoxic agents. Therefore, Herceptin contribution to tumour response outcomes could not be precisely determined and the total number of cases is not sufficient. It is recommended that further work involves a large series of HER2/neu positive salivary gland cancers (randomized control trial) treated with chemotherapy with and without Herceptin. This might need multi-institutional cooperation.

High-throughput profiling identifies clinically actionable mutations in salivary duct carcinoma

Background

Salivary duct carcinoma (SDC) is a highly aggressive subtype of salivary gland cancers and there is no established standard therapy for this disease. Thus, development of molecular markers for SDC will be important to guide the diagnosis and therapy of this aggressive tumor.

Methods

We performed next-generation sequencing using the Ion Torrent AmpliSeq cancer panel, which explores the mutational status of hotspot regions in 50 cancer-associated genes, and we analyzed copy number variations (CNVs) of 21 genes by NanoString nCounter for 37 patients with SDC. Fluorescent in situ hybridization was also conducted to confirm ERBB2 gene amplification. Clinical records and tumor histopathology of the patients were retrospectively reviewed.

Results

Genetic alterations were detected in 29 of 37 (78.3%) tumors, including mutations in PIK3CA (N = 9, 24.3%), ERBB2 (N = 4, 10.8%), and EGFR (N = 4, 10.8%). To our knowledge, this is the first time that ERBB2 mutations have been reported in this tumor type. Both PIK3CA and ERBB2 mutation status were associated with poor overall survival, but without statistical significance. ERBB2 amplification was strong and common in SDC and almost all cases also exhibited EGFR and ERBB3 amplifications.

Conclusions

This study reports the largest and most comprehensive analysis of DNA aberrations in SDC. Our results show that PIK3CA and/or ERBB2 alterations in the development of SDC might be a useful diagnostic tool and could serve as a potential therapeutic target.

PTEN and Ki67 expression is associated with clinicopathologic features of non-small cell lung cancer

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and the proliferating antigen Ki67 have been widely studied in several tumors. However, their role as indicator in non-small cell lung cancer (NSCLC) remains unknown. Here, we investigated the expression of PTEN and Ki67 in NSCLC tissues and paired normal lung tissues to identify whether these proteins are associated with lung cancer development and survival. Immunohistochemistry for PTEN and Ki67 was performed on 67 lung cancer tissues and 41 paired adjacent normal lung tissues to detect the expression of these two proteins. The expression of PTEN in NSCLC tissues (32.8%) was significantly lower than that in normal tissues (82.9%, P < 0.05). In contrast, the expression of Ki67 in NSCLC tissues (76.1%) was significantly higher than that in normal tissues (27.3%, P < 0.05). Expression of both PTEN and Ki67 were strongly associated with tumor histology, clinical stage, lymph node metastasis, differentiation and 4-year postoperative survival rate (P < 0.05). However, PTEN expression was negatively correlated with Ki67 expression (r = -0.279, P < 0.05). In conclusion, low PTEN expression and Ki67 overexpression are associated with malignant invasion and lymph node metastasis of NSCLC. These proteins may serve as diagnostic and prognostic biomarkers of NSCLC.

The prognostic impact of human leukocyte antigen (HLA) class I antigen abnormalities in salivary gland cancer. A clinicopathological study of 288 cases

AIMS

To study abnormalities of proteins of the major histocompatibility complex class I in a series of 288 salivary gland carcinomas, and to correlate findings with patients' overall survival (OS).

METHODS AND RESULTS

Protein expression of human leukocyte antigen (HLA)-A, heavy chain (HC)-10, β2 -microglobulin, low molecular weight polypeptides (LMP) 2 and 7, transporters associated with antigen processing (TAP) 1 and 2, calnexin, calreticulin, endoplasmic reticulum (ER) p57 and tapasin was evaluated by immunohistochemistry and semiquantitatively analyzed. As compared with normal salivary gland tissue, HLA-A, LMP7, TAP2 and HLA class I were significantly down-regulated in salivary gland carcinomas, whereas β2 -microglobulin, calnexin, LMP2, and TAP1 were upregulated. Expression of calreticulin, ERp57 and tapasin was unaltered. In univariate Kaplan-Meier analyses, low expression of LMP7 (P = 0.005) and high expression of β2 -microglobulin (P = 0.028), HLA-A (P < 0.001), TAP1 (P = 0.01), and tapasin (P < 0.001) were significantly associated with shorter OS. In multivariate analysis incorporating tumour stage, nodal/distant metastasis, and grade, HLA-A (P = 0.014), LMP7 (P = 0.033), and tapasin (P = 0.024), as well as distant metastasis (P = 0.012) and high tumour grade (P < 0.001), remained statistically significant.

CONCLUSION

The prognostic influence of up-regulated HLA-A and tapasin and down-regulated LMP7 may provide a rationale for targeting these specific components of the antigen processing and presentation pathway in salivary gland carcinomas.

PIK3CA, HRAS and PTEN in human papillomavirus positive oropharyngeal squamous cell carcinoma

Background

Recent genomic evidence suggests frequent phosphatidylinositide 3-kinase (PI3K) pathway activation in human papillomavirus (HPV) positive oropharyngeal squamous cell carcinoma. Mutations/amplification of the gene encoding p110α catalytic subunit of phosphoinositide 3-kinase (PIK3CA), loss of phosphatase and tensin homolog (PTEN) and HRAS mutations are known to activate PI3K pathway.

Methods and results

PIK3CA mutations were identified by Sanger sequencing in 23 of 75 (31%) HPV-positive oropharyngeal carcinomas, including exon 9 (p.E545K [n = 10] and p.E542K [n = 5]) or exon 20 (p.H1047Y, n = 2) mutations. Five rare and one novel (p.R537Q) PIK3CA mutations were identified. HRAS mutation (p.Q61L) was detected in 1 of 62 tested cases. PIK3CA amplification by fluorescence in situ hybridization (FISH) was identified in 4 cases (4/21, 20%), while PTEN loss was seen in 7 (7/21, 33%) cases (chromosome 10 monosomy [n = 4], homozygous deletion [n = 3]).

Conclusions

Overall, genetic alterations that likely lead to PI3K pathway activation were identified in 34 of 75 cases (45%) and did not correlate with disease specific survival. These findings offer a molecular rationale for therapeutic targeting of PI3K pathway in patients with HPV-positive oropharyngeal carcinoma.

PIK3CA mutations and PTEN loss in salivary duct carcinomas

Salivary duct carcinoma (SDC) is an aggressive malignancy that frequently presents at an advanced stage. Mutations/amplification of the gene encoding the p110α catalytic subunit of phosphoinositide 3-kinase (PIK3CA) and/or loss of the phosphatase and tensin homolog (PTEN) are known to activate the phosphoinositide 3-kinase (PI3K) pathway and may represent a therapeutic target. In 7 of 34 SDCs (20.5%) a SNaPshot polymerase chain reaction detected PIK3CA exon 9 [p.E545K (n=3) and p.E542K (n=2)] or exon 20 [p.H1047R (n=2)] mutations. PIK3CA p.E545K mutation was identified in 3 de novo SDCs with conventional morphology. The only case of SDC with anaplastic transformation showed PIK3CA p.H1047R mutation, whereas 1 of 2 PIK3CA p.E542K mutations was identified in SDC arising in a pleomorphic adenoma. None of the 16 tested SDCs showed PIK3CA amplification by fluorescence in situ hybridization. Fluorescence in situ hybridization identified PTEN loss in 8 of 16 tested SDCs (50%) [homozygous deletion (n=3), chromosome 10 monosomy (n=3), hemizygous deletion (n=2)]. Two cases showed both PIK3CA mutation and PTEN loss, suggesting that these events are not mutually exclusive. These findings offer a molecular rationale for therapeutic targeting of the PI3K pathway in patients with SDC.

Expression levels and significance of nuclear factor-κB and epidermal growth factor receptor in hepatolithiasis associated with intrahepatic cholangiocarcinoma

BACKGROUND

An increasing incidence of cholangiocarcinoma (CCA) and CCA mortality rates has been observed around the world. Patients with intrahepatic biliary stones have a 10% risk of developing CCA, and up to 70% of patients with histologically confirmed CCA have hepatolithiasis. Few previous studies have addressed the associations between the expression of nuclear factor (NF)-κB and epidermal growth factor receptor (EGFR) and clinicopathological prognosis in patients with hepatolithiasis-associated intrahepatic CCA.

AIMS

This study was designed to investigate the clinicopathological and prognostic significance of NF-κB and EGFR expression in hepatolithiasis-associated intrahepatic CCA and hepatolithiasis.

METHODS

A total of 90 liver specimens were immunohistochemically stained for NF-κB and EGFR expression, and the characteristics of 90 individual patients were retrospectively reviewed.

RESULTS

Differences in the positive rates of NF-κB and EGFR expression between the hepatolithiasis-associated intrahepatic CCA group, intrahepatic lithiasis group, and control group were found to be statistically significant. EGFR expression was closely associated with the degree of differentiation and depth of invasion (p < 0.05). The 1-, 3-, and 5-year overall survival rates were respectively 42.8, 21.0, and 10.3% in intrahepatic CCA groups. The survival rate of the EGFR-negative group was higher than in the EGFR-positive group (p < 0.01). Lymph node metastasis (HR 1.24, 95% CI 1.02-1.51) and EGFR positivity (HR 1.74, 95% CI 1.30-2.23) were associated with decreases in the survival rate.

CONCLUSION

The expression of NF-κB may be an early step in intrahepatic cholangiocarcinogenesis. Overexpression of EGFR is associated with the degree of malignancy and with poor prognosis. NF-κB and EGFR may cooperate during intrahepatic cholangiocarcinogenesis and progression. Lymph node metastasis and EGFR positivity were associated with decreases in the survival rate.

Expression and mutational status of treatment-relevant targets and key oncogenes in 123 malignant salivary gland tumours

BACKGROUND

Malignant tumours of the salivary glands (MSGT) are rare and pleomorphic entities. Patients with advanced disease may benefit from targeted therapy; however, specific targets for optimising and personalising treatments are yet to be identified.

DESIGN

Immunohistochemistry for C-KIT, EGFR, HER2, MUC1, phospho-mTOR, androgen/estrogens/progesterone receptors and Ki67 was carried out and evaluated in terms of progression-free and overall survival. High throughput molecular screening of key oncogenes was done in 107 patients using routine diagnostic methods and Sequenom technology.

RESULTS

Several therapy leads were identified, including high levels of HER2 and androgen receptors in salivary duct carcinomas, C-KIT in myoepithelial carcinomas and EGFR in mucoepidermoid carcinomas. Recurrent mutations involving downstream elements of the EGFR pathway were found in HRAS, notably in tumours with a myoepithelial component, and in other key oncogenes (KRAS/NRAS/PI3KCA/BRAF/MAP2K). On the other hand, <1% of samples had EGFR or HER2 mutations.

CONCLUSION

Several tumour subtypes overexpressed targets of directed therapies suggesting potential therapy leads. Genotyping results suggest activation downstream of EGFR in 18 of the 107 samples that could be associated with low efficacy of EGFR inhibitors. Other molecules, such as PI3K/MEK or mTOR inhibitors, may have anti-tumour activity in this subgroup. The high mutation rate in HRAS highlights a novel key oncogenic event in MSGT.

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.

The Justy mutant mouse strain produces a spontaneous murine model of salivary gland cancer with myoepithelial and basal cell differentiation

We previously identified a novel mutant mouse strain on the C3HeB/FeJ background named Justy. This strain bears a recessive mutation in the Gon4l gene that greatly reduces expression of the encoded protein, a nuclear factor implicated in transcriptional regulation. Here, we report that Justy mutant mice aged 6 months or older spontaneously developed carcinomas with myoepithelial and basaloid differentiation in salivary glands with an incidence of ∼25%. Tumors developed proximate to submandibular glands and to a lesser extent in the sublingual and parotid glands. Histologically, tumors often had central cavitary lesions filled with necrotic debris that were lined by tumor cells, and had spindle and epithelioid cell differentiation with lesser basaloid to clear cell features. Tumor tissue often had variable evidence of a high mitotic rate, pleomorphism, and invasion into adjacent salivary glands. Neoplastic cells had diffuse immunoreactivity for pancytokeratin (AE1/AE3) and p63. Although CK5/6 immunostaining was seen in the much of the tumor cells, it was often lacking in pleomorphic areas. Tumor cells lacked immunoreactivity for alpha-smooth muscle actin, S100, c-Kit, and glial fibrillary acid protein. In addition, tumors had immunoreactivity for phosphorylated and total epidermal growth factor receptor, suggesting that EGFR signaling may participate in growth regulation of these tumors. These findings indicate that the salivary gland carcinomas occur spontaneously in Justy mice, and that these tumors may offer a valuable model for study of EGFR regulation. In combination, our data suggest that Justy mice warrant further investigation for use as a mouse model for human salivary gland neoplasia.

Bioinformatics and systems biology analysis of genes network involved in OLP (Oral Lichen Planus) pathogenesis

BACKGROUND

Genes involved in different biological processes form complex interaction networks. However, only few of them have a high number of interactions with the other genes in the network and therefore they may play a major role. In previous bioinformatics and experimental studies, these genes were identified and termed as "leader genes". In the current ab initio theoretical study, genes involved in human OLP (Oral Lichen Planus) pathogenesis are identified and ranked according to their number of interactions, in order to obtain a broader view of its molecular mechanisms and to plan targeted experimentations.

METHODS

Genes involved or potentially involved in OLP were identified by systematically querying several databases until the identification of a final set of genes. Interactions among these genes were mapped and given a significance score using STRING database. For each gene, significance scores were summed to obtain a weighted number of links (WNL) and subsequently genes were clustered according to this parameter. The genes in the highest cluster were termed as leader genes; the other ones were ranked as class B genes, class C genes, and so on. This study was complemented by a topological analysis of the network, carried out using Cytoscape, BinGO and FANMOD software.

RESULTS

The interactions in the obtained network showed power law behaviour, in agreement with the scale-free topology theory of the biological graphs. 132 genes were identified and five of them (namely, JUN, EGFR, FOS, IL2, ITGB4) were classified as leaders. Interestingly, all of them but EGFR were up-regulated and were widely distributed in the network (in term of topological parameters such as stress, eccentricity and radiality) and showed higher topological coefficients than the other genes.

CONCLUSIONS

Even with the limitations of any ab initio analysis, this study can suggest targeted experimentation, focused on the leader genes and therefore simpler to be analysed than mass scale molecular genomics. Moreover, it may suggest new potential risk factors and therapeutic targets.

Conditional Inactivation of Pten with EGFR Overexpression in Schwann Cells Models Sporadic MPNST

The genetic mechanisms involved in the transformation from a benign neurofibroma to a malignant sarcoma in patients with neurofibromatosis-type-1- (NF1-)associated or sporadic malignant peripheral nerve sheath tumors (MPNSTs) remain unclear. It is hypothesized that many genetic changes are involved in transformation. Recently, it has been shown that both phosphatase and tensin homolog (PTEN) and epidermal growth factor receptor (EGFR) play important roles in the initiation of peripheral nerve sheath tumors (PNSTs). In human MPNSTs, PTEN expression is often reduced, while EGFR expression is often induced. We tested if these two genes cooperate in the evolution of PNSTs. Transgenic mice were generated carrying conditional floxed alleles of Pten, and EGFR was expressed under the control of the 2',3'-cyclic nucleotide 3'phosphodiesterase (Cnp) promoter and a desert hedgehog (Dhh) regulatory element driving Cre recombinase transgenic mice (Dhh-Cre). Complete loss of Pten and EGFR overexpression in Schwann cells led to the development of high-grade PNSTs. In vitro experiments using immortalized human Schwann cells demonstrated that loss of PTEN and overexpression of EGFR cooperate to increase cellular proliferation and anchorage-independent colony formation. This mouse model can rapidly recapitulate PNST onset and progression to high-grade PNSTs, as seen in sporadic MPNST patients.

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

Hepatocyte growth factor receptor (MET) is a key driver of oncogenic transformation. Copy number gain and amplification of MET positively enhance tumour growth, invasiveness and metastasis in different cancer types. In the present study, 266 carcinomas of the major and minor salivary glands were investigated for genomic MET status by fluorescence in situ hybridization and for protein expression by immunohistochemistry. Results were matched with clinicopathological parameters, long-term survival and the status of epidermal growth factor receptor (EGFR) and phosphatase and tensin homologue (PTEN). Low polysomy (n = 42), high polysomy (n = 27), amplification (n = 2) and deletion (n = 18) were found as aberrations of genomic MET in certain subtypes. MET aberrations were associated with increased patient age (>70 years, p = 0.003), male gender (p = 0.01), increased tumour size (p = 0.002), lymph node metastases (p < 0.001), high-grade malignancy (p < 0.001) and unfavourable overall survival (p < 0.001). Both copy number gain (p < 0.001) and deletion (p = 0.031) of MET correlated with copy number gain of EGFR. Tumours with genomic loss of PTEN (n = 48) concurrently presented aberration of genomic MET (p < 0.001). MET gene status significantly correlated with protein status (p = 0.038). In conclusion, gain but also loss of genomic MET activity correlates with aggressive tumour growth, nodal metastasis and worse overall survival in salivary gland cancer. Moreover, aberrations of MET are associated with EGFR and PTEN signalling and might possess relevance for targeted therapies of salivary gland carcinomas in the future.

Takahashi R, Nagai T, Yoshida M, Suzuki F, Obikane H, Yamashina M, Matsubayashi J. Immunohistochemical analysis of salivary gland tumors: application for surgical pathology practice

Salivary gland tumors are relatively uncommon and there exists a considerable diagnostic difficulty owing to their diverse histological features in individual lesions and the presence of a number of types and variants, in addition to overlapping histological patterns similar to those observed in different tumor entities. The classification is complex, but is closely relevant to the prognostic and therapeutic aspects. Although hematoxylin-eosin staining is still the gold standard method used for the diagnosis, immunohistochemistry (IHC) can enhance the accuracy and be a helpful tool when in cases to investigate the subjects that cannot be assessed by histological examination, such as the cell nature and differentiation status, cell proliferation, and tumor protein expression. This review depicts on the practical diagnostic utility of IHC in salivary gland tumor pathology under the following issues: assessment of cell differentiation, focusing on neoplastic myoepithelial cells; discrimination of histologically mimic tumor groups; diagnosis of specific tumor types, e.g., pleomorphic adenoma, adenoid cystic carcinoma, and salivary duct carcinoma; and evaluation of malignancy and prognostic factors. IHC plays a limited, even though important, role in the diagnosis of salivary gland tumors, but is often useful to support the histological assessment. However, unfortunately few tumor type-specific markers are still currently available. For these reasons, IHC should be considered a method that can be used to assist the final diagnosis, and its results themselves do not directly indicate a definitive diagnosis.

Functional inactivation of Rb sensitizes cancer cells to TSC2 inactivation induced cell death

We showed previously that inactivation of TSC2 induces death in cancer cells lacking the Retinoblastoma (Rb) tumor suppressor under stress conditions, suggesting that inactivation of TSC2 can potentially be used as an approach to specifically kill cancers that have lost WT Rb. As Rb is often inactivated in cancers by overexpression of cyclin D1, loss of p16(ink4a) cdk inhibitor, or expression of viral oncoproteins, it will be interesting to determine if such functional inactivation of Rb would similarly sensitize cancer cells to TSC2 inactivation induced cell death. In addition, many cancers lack functional Pten, resulting in increased PI3K/Akt signaling that has been shown to modulate E2F-induced cell death. Therefore it will be interesting to test whether loss of Pten will affect TSC2 inactivation induced killing of Rb mutant cancer cells. Here, we show that overexpression of Cyclin D1 or the viral oncogene E1a sensitizes cancer cells to TSC2 knockdown induced cell death and growth inhibition. On the other hand, knockdown of p16(ink4a) sensitizes cancer cells to TSC2 knockdown induced cell death in a manner that is likely dependant on serum induction of Cyclin D1 to inactivate the Rb function. Additionally, we demonstrate that loss of Pten does not interfere with TSC2 knockdown induced cell death in Rb mutant cancer cells. Together, these results suggest that TSC2 is potentially a useful target for a large spectrum of cancer types with an inactivated Rb pathway.

Salivary gland carcinomas

INTRODUCTION

Salivary gland carcinomas are rare tumours of heterogeneous morphology that require distinctive surgical and adjuvant therapy.

METHODS

Relevant studies were electronically searched in PubMed and reviewed for innovative and important information.

RESULTS

Recent insights in genetic alterations like chromosomal aberrations, expression of receptor tyrosine kinases, malfunction of tumour suppressor genes or DNA promoter methylations increased the knowledge about aetiology and pathogenesis. New histological subtypes are recognised, and a three-tiered grading system seems reasonable. Ultrasound remains the basic diagnostic imaging procedure. New developments comprise the diffusion-weighed magnetic resonance imaging, while fluorodeoxyglucose positron emission tomography/computed tomography shows good diagnostic accuracy in detecting distant metastases and local recurrence. Fine-needle aspiration cytology helps in differentiating a neoplasia from a non-neoplastic lesion while being unreliable in recognising malignancy. In contrast, additional core needle biopsy and/or intraoperative frozen section diagnosis increase the accuracy in diagnosing a malignant lesion. Conservative parotid surgery with nerve monitoring remains state-of-the-art. Free flaps or musculoaponeurotic flaps are proposed for prevention of Frey's syndrome. As parotid cancer often shows skip metastases, complete ipsilateral neck dissection (level I-V) is indicated particularly in high-grade lesions. Adjuvant radio(chemo)therapy increases local tumour control, whereas overall survival is not necessarily improved. Current results of systemic chemotherapy or targeted therapy in advanced tumour stages are disappointing.

CONCLUSION

Despite several developments, salivary gland carcinomas remain a heterogeneous group of tumours challenging both pathologists and clinicians.