Immune responses to DNA mismatch repair enzymes hMSH2 and hPMS1 in patients with pancreatic cancer, dermatomyositis and polymyositis

Analysis of the Expression and Prognostic Value of MSH2 in Pan-Cancer Based on Bioinformatics

Background

MutS homolog 2 (MSH2), with the function of identifying mismatches and participating in DNA repair, is the “housekeeping gene” in the mismatch repair (MMR) system. MSH2 deficiency has been reported to enhance cancer susceptibility for the association of hereditary nonpolyposis colorectal cancer. However, the expression and prognostic significance of MSH2 have not been studied from the perspective of pan-cancer.

Methods

The GTEx database was used to analyze the expression of MSH2 in normal tissues. The TCGA database was used to analyze the differential expression of MSH2 in pan-cancers. The prognostic value of MSH2 in pan-cancer was assessed using Cox regression and Kaplan-Meier analysis. Spearman correlations were used to measure the relationship between the expression level of MSH2 in pan-cancer and the level of immune infiltration, tumor mutational burden (TMB), and microsatellite instability (MSI).

Results

MSH2 is highly expressed in most type of cancers and significantly correlated with prognosis. In COAD, KIRC, LIHC, and SKCM, the expression of MSH2 was significantly positively correlated with the abundance of B cells, CD4+ T cells, CD8+ T cells, dendritic cells, macrophages, and neutrophils. In THCA, MSH2 expression correlated with CD8+T Cell showed a significant negative correlation. MSH2 had significantly negative correlations with stromal score and immune score in a variety of cancers and significantly correlated with TMB and MSI of a variety of tumors.

Conclusions

MSH2 may play an important role in the occurrence, development, and immune infiltration of cancer. MSH2 can emerge as a potential biomarker for cancer diagnosis and prognosis.

Autoantibody-targeted TAAs in pancreatic cancer: A comprehensive analysis

BACKGROUND

Pancreatic cancer is one of the leading causes of cancer mortality and lacks efficient biomarkers for early diagnosis. In the early stages of pancreatic cancer, humoral immunity can respond to a certain amount of tumor-associated antigens (TAAs) with the production of corresponding autoantibodies. Such autoantibody-targeted TAAs (autoTAAs) are highly likely to indicate early events during pancreatic carcinogenesis. Herein, we performed a comprehensive analysis of these autoTAAs to explore their physiological function and their involvement and prognostic value in pancreatic cancer.

METHODS

We first searched the literature to identify the autoTAAs. A PPI network of these autoTAAs was constructed, and core network modules were extracted by Cytoscape software. GO annotation and KEGG pathway analysis were performed to analyze the main physiological functions of these autoTAAs. The prognostic value of autoTAAs in pancreatic cancer was analyzed by using RNA-seq data generated by TCGA.

RESULTS

The PPI network including 98 autoTAAs was constructed, and 2 subgroups were extracted as core modules. GO and KEGG analysis revealed that key functions and pathways of these autoTAAs were significantly enriched in nucleotide repair, protein synthesis, and cancer-associated events. MSH2, EZR, PGK1, VCL and ANXA2 have prognostic value in pancreatic cancer, and high mRNA expression of these 5 proteins is associated with unfavorable prognosis in pancreatic cancer.

CONCLUSIONS

AutoTAAs may be associated with early events in the carcinogenesis of pancreatic cancer. MSH2, EZR, PGK1, VCL and ANXA2 predict poor prognosis in pancreatic cancer. Some autoTAAs also have prognostic value in other cancers.

Immunotherapy: Pancreatic Cancer and Extrahepatic Biliary Tract Cancer

Pancreatic ductal adenocarcinoma (PDAC) and extrahepatic biliary tract cancer (BTC) are among the malignancies with the highest morbidity and mortality. Despite increasing knowledge on biology and novel therapies, outcome remains poor in these patients. Recent progress in immunotherapies created new hopes in the treatment of PDAC and extrahepatic BTC. Several trials tested immunotherapies in various therapeutic situations as monotherapies or in combinations. Although responses were seen in some of the trials, the value of immunotherapy in PDAC and extrahepatic BTC remains unclear in the current situation, especially regarding the complex biological characteristics with a high stroma component, intrinsic resistance mechanisms and an immunosuppressive, hypoxic microenvironment. These major hurdles have to be taken into account and overcome if immunotherapies should be successful in these tumor entities. Thereby, combinational approaches that allow on the one hand targeted therapy and on the other restore or boost the function of immune cells are promising.

Serum APE1 as a predictive marker for platinum-based chemotherapy of non-small cell lung cancer patients

Purpose

To define the role of the DNA repair protein apurinic/apyrimidinic endonuclease 1 (APE1) in predicting the prognosis and chemotherapeutic response of non-small cell lung cancer patients receiving platinum-containing chemotherapy.

Results

Our investigations found that serum APE1 level was significantly elevated in 229 of 412 NSCLC patients and correlated with its level in tissue (r² = 0.639, p < 0.001). The elevated APE1 level in both tissue and serum of patients prior to chemotherapy was associated with worse progression-free survival (HR: 2.165, p < 0.001, HR: 1.421, p = 0.012), but not with overall survival. After 6 cycles of chemotherapy, a low APE1 serum level was associated with better overall survival (HR: 0.497, p = 0.010).

Experimental Design

We measured APE1 protein levels in biopsy tissue from 172 NSCLC patients and sera of 412 NSCLC patients receiving platinum-based chemotherapy by immunohistochemistry and a newly established sensitive and specific enzyme-linked immunosorbent assay, respectively. APE1 levels in sera of 523 healthy donors were also determined as control.

Conclusions

Our studies indicate that APE1 is a biomarker for predicting prognosis and therapeutic efficacy in NSCLC. The chemotherapy-naïve serum APE1 level, which correlated with its tissue level inversely associated with progression-free survival of platinum-containing doublet chemotherapy, whereas post-treatment serum APE1 level was inversely associated with overall survival.

Mutations in DNA repair genes are associated with increased neo-antigen load and activated T cell infiltration in lung adenocarcinoma

Mutations in DNA repair genes lead to increased genomic instability and mutation frequency. These mutations represent potential biomarkers for cancer immunotherapy efficacy, as high tumor mutational burden has been associated with increased neo-antigens and tumor infiltrating lymphocytes. While mismatch repair mutations have successfully predicted response to anti-PD-1 therapy in colorectal and other cancers, they have not yet been tested for lung cancer, and few have investigated genes from other DNA repair pathways. We utilized TCGA samples to comprehensively immunophenotype lung tumors and analyze the links between DNA repair mutations, neo-antigen and total mutational burden, and tumor immune infiltration. Overall, 73% of lung tumors contained infiltration by at least one T cell subset, with high mutational burden tumors containing significantly increased infiltration by activated CD4 and CD8 T cells. Further, mutations in mismatch repair genes, homologous recombination genes, or POLE accurately predicted increased tumor mutational burden, neo-antigen load, and T cell infiltration. Finally, neo-antigen load correlated with expression of M1-polarized macrophage genes, PD-1, PD-L1, IFNγ, GZMB, and FASLG, among other immune-related genes. Overall, after defining the immune infiltrate in lung tumors, we demonstrate the potential value of utilizing gene mutations from multiple DNA repair pathways as biomarkers for lung cancer immunotherapy.

A systematic review of serum autoantibodies as biomarkers for pancreatic cancer detection

Pancreatic cancer is a leading cause of cancer-related deaths in the western world. Patients with pancreatic cancer have poor prognosis, partly due to difficulties in detecting it at early stages. While different markers have been associated with pancreatic cancer, many of them show suboptimal sensitivity and specificity. Serum autoantibodies against tumor-associated antigens have recently emerged as early stage biomarkers for different types of cancers. Given the urgent need for early and reliable biomarkers for pancreatic cancer, we undertook a systematic review of the published literature to identify primary articles that evaluated serum autoantibodies in pancreatic cancer detection by searching PubMed and ISI Web of Knowledge. Two reviewers extracted data on study characteristics and results independently. Overall, 31 studies evaluating 124 individual serum autoantibodies in pancreatic cancer detection met the inclusion criteria. In general, single autoantibody markers showed relatively low sensitivities at high specificity. A combination of markers, either multiple serum autoantibodies or serum autoantibodies combined with tumor-associated markers, led to a better diagnostic performance. However, most of the analyzed autoantibodies have only been reported in single studies and therefore need to be independently validated. We conclude that serum autoantibodies might present an option as biomarkers for early detection of pancreatic cancer, but more work is needed to identify and validate autoantibody signatures that are associated with early stage pancreatic cancer.

Cancer vaccines and immunotherapeutic approaches in hepatobiliary and pancreatic cancers

Hepatobiliary and pancreatic cancers along with other gastrointestinal malignancies remain the leading cause of cancer-related deaths worldwide. Strategies developed in the recent years on immunotherapy and cancer vaccines in the setting of primary liver cancer as well as in pancreatic cancer are the scope of this review. Significance of orthotopic and autochthonous animal models which mimic and/or closely reflect human malignancies allowing for a prompt and trustworthy analysis of new therapeutics is underlined. Combinational approaches that on one hand, specifically target a defined cancer-driving pathway, and on the other hand, restore the functions of immune cells, which effector functions are often suppressed by a tumor milieu, are shown to have the strongest perspectives and future directions. Among combinational immunotherapeutic approaches a personalized- and individual cancer case-based therapy is of special importance.

The hMLH1 -93G>A Polymorphism and Risk of Ovarian Cancer in the Chinese Population

Background

As a mismatch repair (MMR) gene, hMLH1 plays an important role in the maintenance of chromosomal integrity. Several studies have investigated the associations of hMLH1 -93G>A (rs1800734) and Ile219Val (rs1799977) in diverse tumor types with discordant results, but their roles in ovarian cancer in the Chinese population remains to be elucidated.

Methods

In a case-control analysis, we assessed the association between these two polymorphisms and ovarian cancer risk in 421 ovarian cancer patients and 689 control subjects in the Chinese population using logistic regression.

Results

We found that the variant hMLH1 genotypes (-93AA and AG) are associated with risk of ovarian cancer (adjusted odds ratio [OR] = 2.02, 95% confidence interval [CI] = 1.42–2.89) compared with the -93GG genotype. The A allele increases the risk of ovarian cancer in a dose-dependent manner (P<10⁻⁴). Functional test showed that -93A allele increased hMLH1 promoter transcriptional activity and the luciferase activity. However, no significant difference was found in the genotype frequencies at the Ile219Val site between the cases and controls.

Conclusions

These findings indicate that the -93G>A polymorphism in hMLH1 may affect ovarian cancer susceptibility in the Chinese population.

Expression of DNA-repair proteins and their significance in pancreatic cancer and non-cancerous pancreatic tissues of Sprague-Dawley rats

Background

To establish a model of pancreatic cancer induced by 7,12-dimethylbenzantracene (DMBA) in Sprague–Dawley (SD) rats, and detect the expression of DNA-repair proteins (MGMT, ERCC₁, hMSH₂, and hMLH₁) and their significance in pancreatic cancer and non-cancerous pancreatic tissues of SD rats.

Methods

DMBA was directly implanted into the parenchyma of rat pancreas (group A and group B), and group B rats were then treated with trichostatin A (TSA). The rats in both groups were executed within 3 to 5 months, and their pancreatic tissues were observed by macrography and under microscopy. Meanwhile, the rats in the control group (group C) were executed at 5 months. Immunohistochemistry was used to assay the expression of MGMT, ERCC₁, hMSH₂, and hMLH₁.

Results

The incidence of pancreatic cancer in group A within 3 to 5 months was 48.7% (18/37), including 1 case of fibrosarcoma. The incidence of pancreatic cancer in group B was 33.3% (12/36), including 1 case of fibrosarcoma. The mean of maximal diameters of tumors in group A was higher than that in group B (P <0.05). No pathological changes were found in pancreas of group C and other main organs (except pancreas) of group A and group B. No statistical differences were found among the positive rates of MGMT, ERCC₁, hMSH₂, and hMLH₁ in ductal adenocarcinoma and non-cancerous pancreatic tissues of group A (P >0.05). The positive rates of MGMT, ERCC₁, hMSH₂, and hMLH₁ were significantly lower in ductal adenocarcinoma than those in non-cancerous tissues of group B (P ≤0.05). All pancreas of group C had positive expression of MGMT, ERCC₁, hMSH₂, and hMLH₁ and two cases of fibrosarcoma showed a negative expression.

Conclusions

DMBA, directly implanted into the parenchyma of pancreas, creates an ideal pancreatic cancer model within a short time. TSA might restrain DNA damage related to the genesis and growth of pancreatic cancer in rats. The DNA-repair proteins, including MGMT, ERCC₁, hMSH₂, and hMLH₁, might play an important role in the genesis of pancreatic cancer induced by DMBA in rats.

The hMLH1 promoter polymorphisms and cancer susceptibility in Asian populations: a meta-analysis

BACKGROUND

A variety of studies have evaluated the associations between polymorphisms in the promoter regions of the hMLH1 and cancer risk. However, the results remain inconclusive. To better understand the roles of the hMLH1 polymorphisms and cancer risk, we conducted a comprehensive meta-analysis to investigate the association between the hMLH1 -93G/A and 1151T/A (Val384Asp) polymorphisms and cancer risk in Asian population.

METHODS

We performed a meta-analysis by conducting searches of the published studies in Pub Med, CNKI, CBM, ISI web of knowledge and Google scholar search databases. Finally, 12 studies were included into our meta-analysis. Overall and subgroup analyses were performed. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the associations between hMLH1 polymorphisms and cancer risk. Statistical analysis was performed with Review Manager 5.0.

RESULTS

Twelve studies addressing two hMLH1 polymorphisms were analyzed among a total of 4128 cancer cases and 4678 controls. For hMLH1 -93G/A, there was no evidence that the hMLH1 -93G/A polymorphism was significantly associated with an increased cancer risk (P>0.05) in Asian populations (heterozygote comparison: OR=0.89 [95% CI (0.75, 1.060)] P=0.20; dominant model comparison: OR=0.98 [95% CI (0.83, 1.15)] P=0.79). In subgroup analysis based on cancer types and the sources of control, no associations were found in colorectal cancer, gastric cancer and "other cancers" under the any gene model except for lung cancer (recessive model comparison: OR=1.69 [95% CI (1.30, 2.19)] P<0.0001). For hMLH1 1151T/A, the polymorphism significantly associated with an increased cancer risk in Asians: OR=1.88 [95% CI (1.49, 2.25)], P<0.0001, and OR=1.87 [95% CI (1.49, 2.25)], P<0.0001.

CONCLUSIONS

Our investigations demonstrated that the hMLH1 -93G/A polymorphism is not a candidate for susceptibility to overall cancers, and that the hMLH1 1151T/A polymorphism is significantly associated with higher cancer risk in Asian populations. Further studies with large sample size for hMLH1 should be conducted.

Cancer-testis antigen BORIS is a novel prognostic marker for patients with esophageal cancer

Esophageal squamous cell cancer (ESCC) is one of the most common lethal tumors in the world, and development of new diagnostic and therapeutic methods is needed. In this study, cancer-testis antigen, BORIS, was isolated by functional cDNA expression cloning using screening technique with serum IgG Abs from ESCC patients. BORIS was previously reported to show cancer-testis antigen like expression, but its immunogenicity has remained unclear in cancer patients. BORIS was considered to be an immunogenic antigen capable of inducing IgG Abs in patients with various cancers, including four of 11 ESCC patients. Immunohistochemical study showed that the BORIS protein was expressed in 28 of 50 (56%) ESCC tissues. The BORIS expression was significantly associated with lymph node metastasis in ESCC patients with pT1 disease (P = 0.036). Furthermore, the patients with BORIS-positive tumors had a poor overall survival (5-year survival rate: BORIS-negative 70.0% vs BORIS-positive 29.9%, log-rank P = 0.028) in Kaplan-Meier survival analysis and log-rank test. Multivariate Cox proportional hazard model demonstrated that BORIS expression was an independent poor prognostic factor (hazard ratio = 4.158 [95% confidence interval 1.494-11.57], P = 0.006). Downregulation of BORIS with specific siRNAs resulted in decreased cell proliferation and invasion ability of ESCC cell lines. BORIS may be a useful biomarker for prognostic diagnosis of ESCC patients and a potential target for treatment including by BORIS-specific immunotherapy and molecular target therapy.

Clinical implications of mismatched repair gene promoter methylation in pancreatic cancer

To investigate the relationship between the hypermethylation statuses of the mismatch repair genes (hMLH1 and hMSH2) promoters and explore the correlation between it and the development of pancreatic cancer and the biological behavior of pancreatic cancer. We selected 90 patients who were diagnosed with pancreatic cancer and underwent radical operations in the First Affiliated Hospital of the Dalian Medical University between January 2002 and June 2008. The methylation status of the hMLH1 and hMSH2 promoters was detected by methylation-specific polymerase chain reaction (MSP). Meanwhile, the expression of hMLH1 and hMSH2 protein was detected by Western blot and immunohistochemistry, and its correlation with biological behavior of pancreatic cancer was explored. Of the 90 cases, hMLH1 promoter methylation was detected in 54 (60.0%) patients, while none of the paracancerous tissues indicated methylation. In the study, the hMLH1-methylated tumors lost hMLH1 protein expression, but the non-hMLH1-methylated tumors were not seen to have a loss of hMLH1 protein expression (P < 0.001). On the other hand, there were four cases of hMSH2 promoter methylation. However, no significant difference was found between hMSH2 promoter methylation and non-hMSH2 promoter methylation cases (P > 0.05). After universal analysis, hMLH1 expression was significantly related to tumor differentiation, lymph node metastasis, and tumor location (P < 0.05) while not related to the age, sex, and tumor size (P > 0.05). Our study suggests that the mismatch repair genes play an important role in pancreatic cancer carcinogenesis and progression through epigenetic modification, and it may be regarded as a potential target for the management of pancreatic cancer.

Pancreatic adenocarcinoma-associated polymyositis treated with corticosteroids along with cancer specific treatment: case report

BACKGROUND

Adenocarcinoma of the pancreas only rarely is associated with inflammatory myopathy. In this setting, polymyositis may be treated with glucocorticoids in combination with cancer specific treatment.

CASE PRESENTATION

We present the case of a 52-year-old man with stage IIA pancreatic tail adenocarcinoma who underwent surgical treatment and six months into therapy with gemcitabine he developed symmetrical, painful, proximal muscle weakness with peripheral oedema. Re-evaluation with imaging modalities, muscle histology and biochemistry conferred the diagnosis of polymyositis associated with pancreatic cancer progression. The patient was treated with glucocorticoids along with gemcitabine and erlotinib which resulted in complete remission within six months. He remained in good health for a further six months on erlotinib maintenance therapy when a new computer tomography scan showed pancreatic cancer relapse and hence prompted 2nd line chemotherapy with gemcitabine.

CONCLUSIONS

Polymyositis associated with pancreatic cancer may respond to glucocorticoids along with cancer specific treatment.

Immunogenicity of SEREX-identified antigens and disease outcome in pancreatic cancer

Despite spontaneous or vaccination-induced immune responses, pancreatic cancer remains one of the most deadly immunotherapy-resistant malignancies. We sought to comprehend the spectrum of pancreatic tumor-associated antigens (pTAAs) and to assess the clinical relevance of their immunogenicity. An autologous SEREX-based screening of a cDNA library constructed from a pancreatic T3N0M0/GIII specimen belonging to a long-term survivor (36 months) revealed 18 immunogenic pTAA. RT-PCR analysis displayed broad distribution of the identified antigens among normal human tissues. PNLIPRP2 and MIA demonstrated the most distinct pancreatic cancer-specific patterns. ELISA-based screening of sera for corresponding autoantibodies revealed that although significantly increased, the immunogenicity of these molecules was not a common feature in pancreatic cancer. QRT-PCR and immunohistochemistry characterized PNLIPRP2 as a robust acinar cell-specific marker whose decreased expression mirrored the disappearance of parenchyma in the diseased organ, but was not related to the presence of PNLIPRP2 autoantibodies. Analyses of MIA-known to be preferentially expressed in malignant cells-surprisingly revealed an inverse correlation between intratumoral gene expression and the emergence of autoantibodies. MIA(high) patients were autoantibody-negative and had shorter median survival when compared with autoantibody-positive MIA(low) patients (12 vs. 34 months). The observed pTAA spectrum comprised molecules associated with acinar, stromal and malignant structures, thus presenting novel targets for tumor cell-specific therapies as well as for approaches based on the bystander effects. Applying the concept of cancer immunoediting to interpret relationships between gene expression, antitumor immune responses, and clinical outcome might better discriminate between past and ongoing immune responses, consequently enabling prognostic stratification of patients and individual adjustment of immunotherapy.

Pathogenic mechanisms of disease in myositis: autoantigens as clues

PURPOSE OF REVIEW

There is increasing evidence of autoimmunity in dermatomyositis and polymyositis, with strong correlations between particular myositis-specific autoantibodies (MSAs) and clinical subsets. It is now clear that corresponding autoantigens are selectively targeted, have distinct adjuvant properties and are upregulated in target tissues, suggesting a role in disease pathogenesis. This review highlights recent findings including the identification of novel MSAs and studies investigating autoantigen properties and expression in both target tissues and tumours.

RECENT FINDINGS

During the review period, the clinical associations of anti-SAE and anti-p140 have been further described. Studies of autoantigen expression have demonstrated upregulation of Mi-2 in response to ultraviolet (UV) damage and expression of myositis-specific autoantigens in rat newborn skeletal muscle. The role of type I interferon and adjuvant activity has also been highlighted through the identification of the CADM140 autoantigen as MDA5, a protein involved in innate immunity.

SUMMARY

There are now a number of models indicating roles of autoantigens in disease pathogenesis. Our increased understanding of the autoantigenic properties of these targeted proteins will help to determine the mechanisms involved in the initiation and propagation of myositis. In turn, these findings may lead to therapeutic advances including the development of more targeted treatments.

Genetic predisposition and environmental risk factors to pancreatic cancer: A review of the literature

Some cases of pancreatic cancer (PC) are described to cluster within families. With the exception of PALLD gene mutations, which explain only a very modest fraction of familial cases, the genetic basis of familial PC is still obscure. Here the literature was reviewed in order to list the known genes, environmental factors, and health conditions associated with PC or involved in the carcinogenesis of the pancreas. Most of the genes listed are responsible for various well-defined cancer syndromes, such as CDKN2A (familial atypical mole-multiple melanoma, FAMMM), the mismatch repair genes (Lynch Syndrome), TP53 (Li-Fraumeni syndrome), APC (familial adenomatous polyposis), and BRCA2 (breast-ovarian familial cancer), where PC is part of the cancer spectrum of the disease. In addition, in this review I ranked known/possible risk factors extending the analysis to the hereditary pancreatitis (HP), diabetes, or to specific environmental exposures such as smoking. It appears that these factors contribute strongly to only a small proportion of PC cases. Recent work has revealed new genes somatically mutated in PC, including alterations within the pathways of Wnt/Notch and DNA mismatch repair. These new insights will help to reveal new candidate genes for the susceptibility to this disease and to better ascertain the actual contribution of the familial forms.

Musculoskeletal syndromes associated with malignancy (excluding hypertrophic osteoarthropathy)

PURPOSE OF REVIEW

To examine recent data about the association between rheumatic disorders and cancer. This article focuses on paraneoplastic rheumatic disorders, which usually precede by a short period of time the diagnosis of malignancy, and on malignant transformation, which occurs late in the course of rheumatic disorders. Evidence of causality between malignancies and rheumatic disorders was reviewed based on statistical indicators (standardized incidence ratios and odds ratios) and by applying Bradford Hill's criteria of causality.

RECENT FINDINGS

Firm epidemiological evidence was found attesting that dermatomyositis and polymyostis may present as paraneoplastic syndromes. Several other musculoskeletal disorders may be present akin to paraneoplastic syndrome, based on clinicians' impressions, but with scarce epidemiological evidence supporting a causal determinism. In contrast, robust evidence has accumulated on the role of longstanding rheumatoid arthritis, Sjögren's syndrome and systemic sclerosis as premalignant conditions. Evidence that systemic lupus erythematosus may evolve into lymphoma is equivocal.

SUMMARY

The link between malignancies and rheumatic disorders may impact on clinical practice. First, paraneoplastic rheumatic syndromes can provide the clinician with hints for earlier diagnosis of occult cancer. Second, the risk of malignant transformation during the course of rheumatic disorders may motivate the search for strategies aimed at prevention.

Mechanisms of disease: autoantigens as clues to the pathogenesis of myositis

Autoimmune inflammatory myopathies, referred to as myositis, comprise a heterogeneous group of chronic inflammatory muscle diseases that present with various clinical phenotypes, histologic changes and autoantibodies, resulting in progressive inflammatory muscle damage and weakness. In up to 20% of myositis patients, particularly those with dermatomyositis, there is an association with cancer that is most frequently diagnosed within 1 year of presentation of myositis. Accumulating data show that autoantibodies in myositis target a specific group of intracellular molecules that are not muscle-specific in their expression. The striking association between autoantibodies recognizing ubiquitously expressed molecules and distinct clinical phenotypes suggests that the target tissues themselves might regulate and shape the phenotype-specific immune response in myositis. Studies indicate that changes in phenotype-specific autoantigens, such as altered structure, enhanced expression, and acquisition of adjuvant properties during various forms of cellular stress, apoptosis, and transformation, might be mechanistically important in this regard. This Review discusses these developments and highlights a central role of autoantigens themselves as a critical partner in driving autoimmune diseases, and the potential for their therapeutic manipulation. In addition, we will highlight insights that the cancer-autoimmunity interface in this group of diseases provides into the relationship between the anticancer immune response and autoimmune diseases.

Polymorphisms in hMLH1 and risk of early-onset lung cancer in a southeast Chinese population

DNA mismatch repair (MMR) plays an important role in maintaining genome stability. Defects in MMR genes have been involved in several types of sporadic and hereditary cancers. hMLH1 is considered one of central members of the MMR pathway. We conducted a hospital-based case-control study to investigate associations of common variations in the hMLH1 gene and risk of lung cancer. A total of 500 cases and 517 controls were genotyped for seven SNPs in hMLH1. Overall, the rs1799977 I219V polymorphism was marginally associated with the risk of lung cancer (P=0.055). This association was much stronger in younger patients (P=0.01; odds ratio, 5.28; 95% CI 1.45-19.21) and lung squamous cell carcinoma (P=0.006; odds ratio, 3.65; 95% CI 1.44-9.24). These findings indicate that the hMLH1 rs1799977 polymorphism may contribute to the etiology of early-onset lung cancer as well as some specific subtype of lung cancer. Larger association studies are warranted to validate our findings and mechanistic studies are needed to elucidate the underlying molecular mechanisms of the association.

Cancer and myositis: new insights into an old association

PURPOSE OF REVIEW

The association between the idiopathic inflammatory myopathies and the development of malignancy has been appreciated for nearly a century, but its meaning and significance have remained unclear. Significant advances in our understanding of the epidemiology and pathophysiology of this association have recently been made. This review will describe the major epidemiological evidence linking inflammatory myopathies with cancer, and will use this evidence to highlight a recently proposed model for the development of cancer-associated myositis.

RECENT FINDINGS

The temporal relationship between the development of cancer and myositis is reminiscent of that seen in neurological paraneoplastic disorders, in which antigens targeted for an immune response are expressed at high levels in the inciting tumor and the affected neuronal tissue. It has also recently been observed that regenerating cells in myositis muscle, but not its normal counterpart, express high levels of myositis-specific autoantigens. These same antigens are expressed at high levels in several cancers known to be associated with the development of myositis, but not in corresponding normal tissue.

SUMMARY

These observations suggest a model of paraneoplasia focusing on common autoantigen expression and immune targeting between cancer tissues and muscle tissue in myositis.