High expression of H3K9me3 is a strong predictor of poor survival in patients with salivary adenoid cystic carcinoma

The Significance of Modified Histone H3 in Epithelial Dysplasia and Oral Cancer

BACKGROUND

Oral carcinogenesis is complex and influenced by both genetic and epigenetic changes. Altered histone modification is the epigenetic event that plays a role in cancer development and progression. Distinct modification patterns of histones have been shown to affect patient prognosis in selected cancers. This study aimed to evaluate the profiles of histone H3 modification in oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC) in association with the clinical-pathologic characteristics.

METHODS

One hundred patients were divided into 4 groups: low-grade OED, high-grade OED, OSCC, and normal oral mucosa (NOM). The levels of 3 types of histone modification-the H3K18ac, H3K9me3, and H3K9ac-were analysed immunohistochemically. Their expression profiles were compared and correlated with prognostically relevant clinical and pathologic features.

RESULTS

The H3K18ac and H3K9me3 were upregulated in OSCC, compared with OED and NOM. In contrast, the H3K9ac was downregulated in low-grade OED but increased in high-grade OED and OSCC. The hyperacetylations of H3K18 and H3K9 significantly correlated with advanced cancer depth of invasion and high T stage, respectively.

CONCLUSIONS

Histone H3 acetylation and methylation at lysine residues are differentially involved in the multistep oral carcinogenesis and impact aggressive cancer phenotypes. The effect of H3K9ac appears early in OED development, whilst the increased H3K18ac and H3K9me3 may be vital in the emergence of OSCC.

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.

Enhanced Transcriptional Signature and Expression of Histone-Modifying Enzymes in Salivary Gland Tumors

Salivary gland tumors (SGTs) are rare and complex neoplasms characterized by heterogenous histology and clinical behavior as well as resistance to systemic therapy. Tumor etiology is currently under elucidation and an interplay of genetic and epigenetic changes has been proposed to contribute to tumor development. In this work, we investigated epigenetic regulators and histone-modifying factors that may alter gene expression and participate in the pathogenesis of SGT neoplasms. We performed a detailed bioinformatic analysis on a publicly available RNA-seq dataset of 94 ACC tissues supplemented with clinical data and respective controls and generated a protein-protein interaction (PPI) network of chromatin and histone modification factors. A significant upregulation of TP53 and histone-modifying enzymes SUV39H1, EZH2, PRMT1, HDAC8, and KDM5B, along with the upregulation of DNA methyltransferase DNMT3A and ubiquitin ligase UHRF1 mRNA levels, as well as a downregulation of lysine acetyltransferase KAT2B levels, were detected in ACC tissues. The protein expression of p53, SUV39H1, EZH2, and HDAC8 was further validated in SGT tissues along with their functional deposition of the repressive histone marks H3K9me3 and H3K27me3, respectively. Overall, this study is the first to detect a network of interacting proteins affecting chromatin structure and histone modifications in salivary gland tumor cells, further providing mechanistic insights in the molecular profile of SGTs that confer to altered gene expression programs.

Targeting drug-tolerant cells: A promising strategy for overcoming acquired drug resistance in cancer cells

Drug resistance remains the greatest challenge in improving outcomes for cancer patients who receive chemotherapy and targeted therapy. Surmounting evidence suggests that a subpopulation of cancer cells could escape intense selective drug treatment by entering a drug-tolerant state without genetic variations. These drug-tolerant cells (DTCs) are characterized with a slow proliferation rate and a reversible phenotype. They reside in the tumor region and may serve as a reservoir for resistant phenotypes. The survival of DTCs is regulated by epigenetic modifications, transcriptional regulation, mRNA translation remodeling, metabolic changes, antiapoptosis, interactions with the tumor microenvironment, and activation of signaling pathways. Thus, targeting the regulators of DTCs opens a new avenue for the treatment of therapy-resistant tumors. In this review, we first provide an overview of common characteristics of DTCs and the regulating networks in DTCs development. We also discuss the potential therapeutic opportunities to target DTCs. Last, we discuss the current challenges and prospects of the DTC-targeting approach to overcome acquired drug resistance. Reviewing the latest developments in DTC research could be essential in discovering of methods to eliminate DTCs, which may represent a novel therapeutic strategy for preventing drug resistance in the future.

Dynamic de novo heterochromatin assembly and disassembly at replication forks ensures fork stability

Chromatin is dynamically reorganized when DNA replication forks are challenged. However, the process of epigenetic reorganization and its implication for fork stability is poorly understood. Here we discover a checkpoint-regulated cascade of chromatin signalling that activates the histone methyltransferase EHMT2/G9a to catalyse heterochromatin assembly at stressed replication forks. Using biochemical and single molecule chromatin fibre approaches, we show that G9a together with SUV39h1 induces chromatin compaction by accumulating the repressive modifications, H3K9me1/me2/me3, in the vicinity of stressed replication forks. This closed conformation is also favoured by the G9a-dependent exclusion of the H3K9-demethylase JMJD1A/KDM3A, which facilitates heterochromatin disassembly upon fork restart. Untimely heterochromatin disassembly from stressed forks by KDM3A enables PRIMPOL access, triggering single-stranded DNA gap formation and sensitizing cells towards chemotherapeutic drugs. These findings may help in explaining chemotherapy resistance and poor prognosis observed in patients with cancer displaying elevated levels of G9a/H3K9me3.

Role of Histone Deacetylases in the Pathogenesis of Salivary Gland Tumors and Therapeutic Targeting Options

Salivary gland tumors (SGTs) comprise a rare and heterogenous category of benign/malignant neoplasms with progressively increasing knowledge of the molecular mechanisms underpinning their pathogenesis, poor prognosis, and therapeutic treatment efficacy. Emerging data are pointing toward an interplay of genetic and epigenetic factors contributing to their heterogeneity and diverse clinical phenotypes. Post-translational histone modifications such as histone acetylation/deacetylation have been shown to actively participate in the pathobiology of SGTs, further suggesting that histone deacetylating factors (HDACs), selective or pan-HDAC inhibitors (HDACis), might present effective treatment options for these neoplasms. Herein, we describe the molecular and epigenetic mechanisms underlying the pathology of the different types of SGTs, focusing on histone acetylation/deacetylation effects on gene expression as well as the progress of HDACis in SGT therapy and the current status of relevant clinical trials.

The Epigenesis of Salivary Glands Carcinoma: From Field Cancerization to Carcinogenesis

Salivary gland carcinomas (SGCs) are a diverse collection of malignant tumors with marked differences in biological activity, clinical presentation and microscopic appearance. Although the etiology is varied, secondary radiation, oncogenic viruses as well as chromosomal rearrangements have all been linked to the formation of SGCs. Epigenetic modifications may also contribute to the genesis and progression of SGCs. Epigenetic modifications are any heritable changes in gene expression that are not caused by changes in DNA sequence. It is now widely accepted that epigenetics plays an important role in SGCs development. A basic epigenetic process that has been linked to a variety of pathological as well as physiological conditions including cancer formation, is DNA methylation. Transcriptional repression is caused by CpG islands hypermethylation at gene promoters, whereas hypomethylation causes overexpression of a gene. Epigenetic changes in SGCs have been identified, and they have been linked to the genesis, progression as well as prognosis of these neoplasms. Thus, we conduct a thorough evaluation of the currently known evidence on the involvement of epigenetic processes in SGCs.

Analysis of Cytological Misdiagnosis and Oversight of Adenoid Cystic Carcinoma of Salivary Gland

OBJECTIVE

In this article on adenoid cystic carcinoma (ACC) of salivary gland, we intend to summarize the causes of misdiagnosis and oversight of ACC hoping to improve cytological diagnostic accuracy, clinical management and patient treatment.

METHODS

The study retrospectively reviewed 32 patients with ACC of salivary gland, registered at the Affiliated Hospital of Southwest Medical University from July 2014 to June 2021. These cases were diagnosed by FNA and surgical excision biopsy. All cytopathological results were retrospectively categorized according to Milan system for reporting salivary gland cytopathology (MSRSGC). The accuracy of FNA was verified by surgical excision biopsy.

RESULTS

Of these 32 patients, 16 (50.0%) cases were male, and 16 (50.0%) were female. Their age ranged from 21 to 79 years, with an average age of 50.32 years. The highest incidence (15/32, 46.9%) of ACC was observed in patients between 41 and 50 years of age. 10 cases (31.3%) occurred in the parotid gland, 9 cases (28.1%) in the submandibular gland, 9 cases (28.1%) in the sublingual gland, 3 cases (9.4%) in the palate, and 1 case (3.1%) in the lip. Among the 32 cases of ACC, 23 cases (71.9%) were classified to VI, 4 cases (12.5%) to IVa, and 5 cases (15.6%) to II by MSRSGC. A comparison of the FNA results with biopsy showed that the accuracy of FNA in ACC of salivary gland is 71.9%. Being able to identify the cytomorphological features is the key factor for accurate diagnosis of ACC of the salivary gland.

CONCLUSION

Our results confirm that FNA is an important initial screening in the diagnosis of ACC of salivary gland. Increased study of the cytomorphology of ACC is beneficial for more accurate diagnosis of ACC, to reduce misdiagnosis and oversight.

Distinct histone H3 modification profiles correlate with aggressive characteristics of salivary gland neoplasms

Post-translational modification of histones is the crucial event that affect many tumor-specific traits. A diverse type of histone modifications had been reported in different cancers with prognostic implications. This study aimed to examine the degree of histone H3 modifications in salivary gland neoplasms and their associations with tumor pathologic characteristics and proliferative activity. The expression of H3K9Ac, H3K18Ac, H3K9Me3 and Ki-67 in 70 specimens of salivary gland neoplasms, consisting of 30 mucoepidermoid carcinoma (MEC), 20 adenoid cystic carcinoma (ACC) and 20 pleomorphic adenoma (PA), were investigated immunohistochemically. The immunohistochemical scoring of 3 histone modification types and Ki-67 labeling index were determined. Overall, MEC demonstrated elevated H3K9Ac level compared with benign PA. Increased H3K9Me3 in MEC was positively correlated with small nest invasion at tumor front, advanced pathologic grade, and elevated proliferative index. In addition, the significant upregulation of all 3 types of histone H3 modification was noted in solid subtype of ACC and associated with increased cell proliferation. This study indicates that salivary gland neoplasms differentially acquire distinct patterns of histone H3 modification, which impact prognostically relevant cancer phenotypes. The hyperacetylation and methylation of histone H3 could be underpinning the prognostically worsen solid type of ACC, and the trimethylation of H3K9 may be involved in aggressive characteristics of MEC.

Low H3K9me3 Expression Is Associated With Poor Prognosis in Patients With Distal Common Bile Duct Cancer

BACKGROUND/AIM

Histone modification is associated with tumorigenesis and cancer progression. Recent studies have revealed the prognostic value of histone modification; however, its prognostic role in distal bile duct cancer remains unclear.

PATIENTS AND METHODS

We analyzed the expression of H3K9me3, H4K20me3, and H3K36me3 and its correlation with survival outcomes in resected samples from 88 patients with distal bile duct cancer.

RESULTS

Low expression rates of H3K9me3, H4K20me3, and H3K36me3 were significantly associated with poor overall survival (p=0.003, 0.008, and 0.047, respectively) and event-free survival (p=0.03 for H3K9m3). Additionally, low-expression of H3K9me3 was an independent poor prognostic indicator (p<0.001; HR=7.85; 95% CI=2.693-22.883).

CONCLUSION

H3K9me3 was an independent poor prognostic factor in distal common bile duct cancer. Our results suggest that histone markers are potential prognostic markers and provide better management for patients at risk for an aggressive course of disease.

Epigenetic Regulatory Enzymes: mutation Prevalence and Coexistence in Cancers

Epigenetic regulation is an important layer of transcriptional control with the particularity to affect the broad spectrum of genome. Over the years, largely due to the substantial number of recurrent mutations, there have been hundreds of novel driver genes characterized in various cancers. Additionally, the relative contribution of two dysregulated epigenomic entities (DNA methylation and histone modifications) that gradually drive the cancer phenotype remains in the research focus. However, a complex scenario arises when the disease phenotype does not harbor any relevant mutation or an abnormal transcription level. Although the cancer landscape involves the contribution of multiple genetic and non-genetic factors, herein, we discuss specifically the mutation spectrum of epigenetically-related enzymes in cancer. In addition, we address the coexistence of these two epigenetic entities in malignant human diseases, especially cancer. We suggest that the study of epigenetically-related somatic mutations in the early cellular differentiation stage of embryonic development might help to understand their later-staged footprints in the cancer genome. Furthermore, understanding the co-occurrence and/or inverse association of different disease types and redefining the general definition of "healthy" controls could provide insights into the genome reorganization.

High methylation levels of histone H3 lysine 9 associated with activation of hypoxia-inducible factor 1α (HIF-1α) predict patients' worse prognosis in human hepatocellular carcinomas

Although it is becoming increasingly apparent that histone methyltransferases and histone demethylases play crucial roles in the cellular response to hypoxia, the impact of hypoxic environments on global patterns of histone methylation is not well demonstrated. In this study, we try to detect the global levels of histone lysine methylation in HCC cases and analyze the correlation between these modifications and the activation of hypoxia-inducible factor 1α (HIF-1α). Immunohistochemistry was used to detect the global levels of histone H3 lysine 9 dimethylation (H3K9me2), histone H3 lysine 9 trimethylation (H3K9me3), histone H3 lysine 27 trimethylation (H3K27me3) and the nuclear expression of HIF-1α in tissue arrays from 111 paraffin-embedded HCC samples. Our analyses revealed that the global levels of H3K9me2, H3K9me3 and the nuclear expression of HIF-1α were distinctly higher in HCC tissues than in peritumoral tissues. Both H3K9me2 and H3K9me3 were positively correlated with the degree of tumor differentiation and the patients' prognosis. Analysis based on the Pearson's correlation coefficient indicated a positive correlation between H3K9me2 and the nuclear expression of HIF-1α, and meanwhile, a significant correlation between the expression of H3K9me2 and H3K9me3 was also found. In addition, the combination of H3K9me2, H3K9me3 and HIF-1α, rather than one single histone modification or molecular maker, is a better prognostic maker for HCC patients. These findings provide new insights on the complex networks underlying cellular and genomic regulation in response to hypoxia and may provide novel targets for future therapies.

Epigenetic alterations in salivary gland tumors

Salivary gland tumors (SGTs) comprise a heterogeneous group of benign and malignant neoplasms that exhibit significant variability in their microscopic appearance, clinical presentation, and biological behavior. The etiologic factors are unknown; however, chromosomic translocation, secondary radiation, and chemotherapy can be associated with the development of SGT. It has been indicated that epigenetic alterations can be responsible for the development and progress of these neoplasms. The epigenetic mechanisms are defined as a set of DNA changes that do not alter the sequence of nucleotide bases but alter the expression of the proteins. These alterations have been studied in the SGT, and they were associated with the development and progress of these neoplasms and may influence on SGT prognosis. Hence, we critically review the currently available data on the participation of epigenetic events on salivary gland tumors.

JMJD1A, H3K9me1, H3K9me2 and ADM expression as prognostic markers in oral and oropharyngeal squamous cell carcinoma

Aims

Jumonji Domain-Containing 1A (JMJD1A) protein promotes demethylation of histones, especially at lysin-9 of di-methylated histone H3 (H3K9me2) or mono-methylated (H3K9me1). Increased levels of H3 histone methylation at lysin-9 (H3K9) is related to tumor suppressor gene silencing. JMJD1A gene target Adrenomeduline (ADM) has shown to promote cell growth and tumorigenesis. JMJD1A and ADM expression, as well as H3K9 methylation level have been related with development risk and prognosis of several tumor types.

Methods and results

We aimed to evaluate JMJD1A, ADM, H3K9me1 and H3K9me2expression in paraffin-embedded tissue microarrays from 84 oral and oropharyngeal squamous cell carcinoma samples through immunohistochemistry analysis. Our results showed that nuclear JMJD1A expression was related to lymph node metastasis risk. In addition, JMJD1A cytoplasmic expression was an independent risk marker for advanced tumor stages. H3K9me1 cytoplasmic expression was associated with reduced disease-specific death risk. Furthermore, high H3K9me2 nuclear expression was associated with worse specific-disease and disease-free survival. Finally, high ADM cytoplasmic expression was an independent marker of lymph node metastasis risk.

Conclusion

JMJD1A, H3K9me1/2 and ADM expression may be predictor markers of progression and prognosis in oral and oropharynx cancer patients, as well as putative therapeutic targets.

Distinct histone modifications denote early stress-induced drug tolerance in cancer

Besides somatic mutations or drug efflux, epigenetic reprogramming can lead to acquired drug resistance. We recently have identified early stress-induced multi-drug tolerant cancer cells termed induced drug-tolerant cells (IDTCs). Here, IDTCs were generated using different types of cancer cell lines; melanoma, lung, breast and colon cancer. A common loss of the H3K4me3 and H3K27me3 and gain of H3K9me3 mark was observed as a significant response to drug exposure or nutrient starvation in IDTCs. These epigenetic changes were reversible upon drug holidays. Microarray, qRT-PCR and protein expression data confirmed the up-regulation of histone methyltransferases (SETDB1 and SETDB2) which contribute to the accumulation of H3K9me3 concomitantly in the different cancer types. Genome-wide studies suggest that transcriptional repression of genes is due to concordant loss of H3K4me3 and regional increment of H3K9me3. Conversely, genome-wide CpG site-specific DNA methylation showed no common changes at the IDTC state. This suggests that distinct histone methylation patterns rather than DNA methylation are driving the transition from parental to IDTCs. In addition, silencing of SETDB1/2 reversed multi drug tolerance. Alterations of histone marks in early multi-drug tolerance with an increment in H3K9me3 and loss of H3K4me3/H3K27me3 is neither exclusive for any particular stress response nor cancer type specific but rather a generic response.

Mutant p53 perturbs DNA replication checkpoint control through TopBP1 and Treslin

Accumulating evidence supports the gain-of-function of mutant forms of p53 (mutp53s). However, whether mutp53 directly perturbs the DNA replication checkpoint remains unclear. Previously, we have demonstrated that TopBP1 forms a complex with mutp53s and mediates their gain-of-function through NF-Y and p63/p73. Akt phosphorylates TopBP1 and induces its oligomerization, which inhibits its ATR-activating function. Here we show that various contact and conformational mutp53s bypass Akt to induce TopBP1 oligomerization and attenuate ATR checkpoint response during replication stress. The effect on ATR response caused by mutp53 can be exploited in a synthetic lethality strategy, as depletion of another ATR activator, DNA2, in mutp53-R273H-expressing cancer cells renders cells hypersensitive to cisplatin. Expression of mutp53-R273H also makes cancer cells more sensitive to DNA2 depletion or DNA2 inhibitors. In addition to ATR-activating function during replication stress, TopBP1 interacts with Treslin in a Cdk-dependent manner to initiate DNA replication during normal growth. We find that mutp53 also interferes with TopBP1 replication function. Several contact, but not conformational, mutp53s enhance the interaction between TopBP1 and Treslin and promote DNA replication despite the presence of a Cdk2 inhibitor. Together, these data uncover two distinct mechanisms by which mutp53 enhances DNA replication: (i) Both contact and conformational mutp53s can bind TopBP1 and attenuate the checkpoint response to replication stress, and (ii) during normal growth, contact (but not conformational) mutp53s can override the Cdk2 requirement to promote replication by facilitating the TopBP1/Treslin interaction.

EZH2 is a sensitive marker of malignancy in salivary gland tumors

BACKGROUND

The immunohistochemical detection of Enhancer of zeste homologue 2 (EZH2) proved to be a useful tool to recognize the malignant nature of tumors in a wide variety of neoplasms. The histological diagnostics of salivary gland tumors is a challenging task, and a reliable marker of malignancy would be extremely helpful.

METHODS

EZH2 expression was investigated in 54 malignant and 40 benign salivary gland tumors of various histological types by standard immunohistochemistry.

RESULTS

The majority (n = 52) of the malignant tumors stained positively, while all the investigated benign tumors were negative for EZH2.

CONCLUSIONS

EZH2 expression in salivary gland tumors, similarly to the tumors of other organs is not characteristic for any tumor type, but is a solid marker of the malignant nature of the tumors.

Hepatitis B virus X protein induces the histone H3 lysine 9 trimethylation on the promoter of p16 gene in hepatocarcinogenesis

Our previous study showed hepatitis B virus X protein (HBx) suppresses the p16 expression in hepatocarcinogenesis. In this study we explored the relationship between HBx and trimethylation of H3K9 (H3K9me3), and elucidated the underlying mechanisms in HBx inducing the tumor suppressor p16 gene silence. SMMC-7721 and HepG2 hepatoma cell lines were transfected with HBx-expressing plasmid. Immunohistochemistry, Western blotting and real-time polymerase chain reaction, were performed to detect the expressions of HBx, H3K9me3, and jumonji domain-containing protein 2B (JMJd2B). H3K9me3 enrichment on the p16 promoter was measured by immunoprecipitation-PCR (ChIP-PCR) analyses, and 39 cases of hepatitis B virus (HBV) associated-hepatocellular carcinoma (HCC) and corresponding noncancerous liver tissues were also examined. We demonstrated that HBx was able to upregulate H3K9me3 and suppress JMJd2B mRNA and protein levels in SMMC-7721 and HepG2 hepatoma cell lines. JMJd2B, as a specific target of H3K9me3 for demethylation, was inversely correlated with the levels of H3K9me3 in SMMC-7721 (r=-0.666, P<0.05) and HepG2 cells (r=-0.625, P<0.05). The ChIP-PCR data indicated that HBx remarkably increased H3K9me3 on the p16 promoter region. Immunohistochemistry analysis showed that H3K9me3 expression in HBx positive HCC samples were significantly higher than that in HBx negative HCC tissues and were associated with decreased levels of JMJd2B expression. JMJd2B immunoreactivity was also remarkably inversed to that of HBx in HCC tissues (r=-0.630, P<0.05). Our results provide evidence that HBx is able to induce H3K9me3 on the p16 promoter via the decrease of demethylase JMJd2B expression and thus promote the repression of p16 gene expression to enhance hepatocarcinogenesis.

Low expression of endothelin receptor B (EDNRB) is related to H3K9me3 binding with the EDNRB promoter region and is associated with the clinical T tumor stage in salivary adenoid cystic carcinoma

OBJECTIVE

To investigate the endothelin receptor B (EDNRB) expression in salivary adenoid cystic carcinoma (ACC) and the mechanism of the regulation of EDNRB expression.

STUDY DESIGN

After screening, EDNRB was selected, and the expression was detected using immunohistochemistry in 33 ACC samples (including 6 clinical tumor stage 1 [T1] patients, 13 T2 patients, 9 T3 patients, and 5 T4 patients) and 20 adjacent glands. Interaction between the EDNRB promoter region and histone H3 lysine 9 trimethylation (H3K9me3) was examined using chromatin immunoprecipitation (ChIP) in combination with ChIP-polymerase chain reaction (ChIP-PCR). EDNRB expression in ACC cells treated with chaetocin was detected using quantitative real-time PCR (qRT-PCR) and Western blot tests.

RESULTS

EDNRB expression was lower in ACC than that in adjacent glands (P = .006). The expression of EDNRB in patients with advanced T stage was lower than that in patients with early T stage (P = .024). The low EDNRB gene expression group had more H3K9me3 binding regions in the gene promoter (P = .003). EDNRB gene expression significantly increased in the ACC cell lines after treatment with chaetocin. Chaetocin could reduce the interaction between the EDNRB promoter and H3K9me3.

CONCLUSIONS

H3K9me3 binding to the EDNRB promoter region could reduce the EDNRB expression. Low EDNRB expression played a role in the progression of ACC tumors.

Distant Metastases in Patients with Carcinoma of the Major Salivary Glands

BACKGROUND

This study aimed to show the incidence of distant metastases (DM) in salivary gland cancer as well as the types of histology most commonly associated with it and to identify factors predictive of DM.

METHODS

The study identified 301 patients who underwent surgery for cancer of the major salivary glands at Memorial Sloan-Kettering Cancer center between 1985 and 2009. Clinical, tumor, and treatment characteristics were recorded. Tumors were categorized as low-, intermediate-, and high-risk pathology based on histologic subtype and grade. Factors predictive of distant recurrence-free probability (DRFP) were determined by uni- and multivariable analyses.

RESULTS

The primary tumor was parotid in 266 patients (88 %), and 96 tumors (32 %) were clinical T3/T4. For 57 patients (18.9 %), DM developed with a 5-year DRFP of 72.7 %. The most common site of metastasis was the lung (50 %). The clinical predictors were male gender, cT4 stage, cN+ stage, and clinical overall stage. The multivariable analysis of clinical variables showed male gender (p = 0.018), cT4 stage (p < 0.001), and cN+ stage (p = 0.004) to be significant. The pathologic predictors were high-risk and high-grade pathology, vascular invasion, perineural invasion, positive margins, pT4 stage, pN+ stage, and overall stage. The multivariable analysis of pathologic variables showed high-grade pathology (p < 0.001), perineural invasion (p = 0.005), and pN+ stage (p = 0.002) to be significant.

CONCLUSIONS

Distant metastases developed in approximately 20 % of the patients with salivary gland cancer. The most common site of metastases was the lung. The significant predictors of DM were cT4, cN+, male gender, high-grade pathology, perineural invasion, and positive nodal disease.

Review and Updates of Immunohistochemistry in Selected Salivary Gland and Head and Neck Tumors

Context

Immunohistochemistry is a useful tool for diagnosing salivary gland and head and neck tumors.

Objective

To review immunohistochemical markers, which can aid in the diagnosis of selected salivary gland and head and neck tumors.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

Salivary gland and head and neck tumors include a large diverse group of tumors with complex and overlapping histologic features. Immunohistochemistry plays an important role in resolving the differential diagnosis of some salivary gland and head and neck tumors and can provide information for the prognosis of certain tumors.

Common features of chromatin in aging and cancer: cause or coincidence?

Age is a major risk factor for cancer. Alterations in DNA methylation, histone modifications, chromatin structure, and epigenetic regulatory mechanisms are prominent hallmarks of both the aging process and cancer. Intriguingly--or possibly coincidentally--several chromatin features are common between aging and cancer. Here we ask whether, and if so how, aging-associated chromatin modifications contribute to tumor susceptibility and tumorigenesis.

Histone trimethylation at H3K4, H3K9 and H4K20 correlates with patient survival and tumor recurrence in early-stage colon cancer

Background

Post-translational modification of histone tails by methylation plays an important role in tumorigenesis. In this study, we investigated the nuclear expression of H3K4me3, H3K9me3 and H4K20me3 in early-stage colon cancer in relation to clinical outcome.

Methods

Tumor tissue cores of 254 TNM stage I-III colorectal cancer patients were immunohistochemically stained for H3K4me3, H3K9me3 and H4K20me3 and scored using the semi-automated Ariol system. Cox proportional hazard trend analyses were performed to assess the prognostic value of the combined markers with respect to patient survival and tumor recurrence.

Results

The histone methylation markers only showed prognostic value in early-stage (TNM stage I and II) colon cancer. Therefore, only this patient set (n = 121) was used for further statistical analyses. Low nuclear expression of H3K4me3, and high expression of H3K9me3 and H4K20me3 were associated with good prognosis. In combined marker analyses, the patient group showing most favorable expression (low H3K4me3, high H3K9me3 and high H4K20me3) was associated with the best prognosis. Multivariate trend analyses showed significantly increased hazard ratios (HR) for each additional marker showing unfavorable expression, as compared to the “all favorable” reference group. The HR for disease-free survival was 3.81 (1.72-8.45; p = 0.001), for locoregional recurrence-free survival 2.86 (1.59-5.13; p < 0.001) and for distant recurrence-free survival 2.94 (1.66-5.22; p < 0.001).

Conclusions

Combined nuclear expression of histone modifications H3K4me3, H3K9me3 and H4K20me3 is prognostic in early-stage colon cancer. The combination of expression of the three histone modifications provides better stratification of patient groups as compared to the individual markers and provides a good risk assessment for each patient group.