Interferon-gamma plasma levels and presence of mouse mammary tumor virus-like env gene: Implications on the pathogenesis of breast cancer

Mouse mammary tumor virus (MMTV) is a retrovirus that has been associated with the development of breast cancer (BC) in mice. The identification of a 95% homologous gene sequence to MMTV in human BC samples has increased interest in this hypothesis. This virus in humans received the name of mouse mammary tumor virus-like (MMTV-like). Several cytokines may be involved in the interactions between MMTV and the immune system, such as interferon-gamma (IFN-γ), which can enhance Th1-mediated antitumor immune response but it can also play a protumorigenic role by transmitting antiapoptotic and proliferative signals. Little is known about the antiviral immune response in a microenvironment with the presence of MMTV-like in BC patients. Therefore, the purpose of the present study was to quantify the plasma levels of IFN-γ in the peripheral blood of 123 neoplasia-free donors and 98 BC patients of different molecular subtypes, by enzyme-linked immunosorbent assay (ELISA), and evaluate the association of these plasma levels with the detection of the MMTV-like env gene in tumor tissue. Correlation analyzes involving IFN-γ plasma levels and clinical-pathological parameters were performed by Kendall Tau-c test. In our study, a decrease in IFN-γ levels was observed in the group of BC patients (30.85 ± 57.49 pg/ml) compared to the control group (115.00 ± 176.80 pg/ml) (p < 0.0001). In the analysis by stratified BC molecular subtypes, Luminal-A (30.79 ± 61.04 pg/ml; p < 0.0001), Luminal-B (24.74 ± 25.78 pg/ml; p = 0.0188) and triple-negative (23.95 ± 40.45 pg/ml; p = 0.0005) had a lower plasma level compared to control group. There was no significant difference between IFN-γ plasma levels of MMTV-like DNA positive samples compared to MMTV-negative samples (p = 0.2056). In general BC, patients with larger tumor size had higher IFN-γ plasma levels (Tau-c = 0.202; p = 0.019). By analyzing the MMTV-like env negative samples, we could identify that IFN-γ plasma levels were higher in larger tumor size (Tau-c = 0.222; p = 0.020) and with greater lymph node involvement (Tau-c = 0.258; p = 0.042). Also, higher IFN-γ plasma levels were observed in patients with higher histopathological grades (Tau-c = 0.384; p = 0.019) in MMTV-like env positive samples. For the first time, we assessed the association between plasma levels of IFN-γ and the presence of the MMTV-like env gene in BC samples. However, more studies are needed to clarify whether the high levels of IFN-γ in MMTV-like env positive samples are reflecting a possible antiviral immune response or whether this cytokine is promoting tumor growth.

An association between chronic life stressors prior to diagnosis of breast cancer

The clinical course of breast cancer (BC) and survival depend on a wide range of risk factors. From the psychosomatic point of view, BC is one of the most studied type of cancer but there is no evidence available for this relation. Therefore, in the present study we evaluate the impact of chronic life stressors in BC patients. A total of 100 BC patients were invited to participate in an interview, when information about social parameters and emotional changes in the period prior to diagnosis were collected. The emotional changes were evaluated by the Holmes and Rahe's Stress Scale, which analyzes the difficulty required for a person to readjust to society after significant changes in their life. Clinicopathological parameters were obtained from the medical records. For all data, the level of significance adopted was p <0.05. It was observed that 55.2 % of the patients have a medium and 13.8 % were at high risk for disease development related to stressful events in the period prior to the BC diagnosis. The highest stress levels were presented by separated, divorced, or widowed patients compared to married (p <0.01) and single (p = 0.037) patients. The high-risk (HR) group had a lower proportion of positivity for estrogen receptor when compared to the low (LR) and moderate risk (MR) groups (p= 0.001). In addition, a binary logistic regression analysis was performed, and we found that the relationship between the estrogen receptor and the HR of chronic stress was independently associated with the histological type of BC and lymph nodes involvement. The relationship of stressful life experiences and BC is not well established, so our study collaborates with the literature to demonstrate the importance of stress as a factor associated with the development of BC.

Mouse Mammary Tumor Virus (MMTV)-Like env Sequence in Brazilian Breast Cancer Samples: Implications in Clinicopathological Parameters in Molecular Subtypes

Background: Breast cancer (BC) is a complex disease in which susceptibility and clinical course depend on multiple factors. Evidence suggests that a mouse mammary tumor virus (MMTV)-homolog may be present in human BCs; however, little is known about its clinical implications. Methods: MMTV-like env nucleotide-sequence was searched in tumor and tumor-adjacent tissues from 217 Brazilian BC patients through nested-PCR and confirmed through PCR-sequencing. Blood samples were also tested for patients with MMTV-like env gene-positive tumors. Correlations with clinicopathological parameters were evaluated. Results: MMTV-like env sequence was detected in tumor and tumor-adjacent tissue samples from 41/217 and 30/196 patients, respectively. In blood, MMTV-like was detected in 17/32 patients. In Luminal-B tumors, MMTV-like in tumor tissue was negatively correlated with tumor size and disease stage, whereas in HER2 tumors it anti-correlated with lymph node metastasis (LNM) and disease stage. Considering blood, MMTV-like env gene positivity negatively correlated with age in general BC, while in Luminal-A tumors it positively correlated with Ki67 but negatively correlated with age and LNM. The associations with decreased LNM frequency were independent of other prognostic factors. Conclusion: MMTV-like env positivity is associated with better prognostic parameters in BC subtypes, which might be explainable by its anti-metastatic potential and by putative activation of immune milieu.

Wilms' tumor susceptibility: possible involvement of FOXP3 and CXCL12 genes

Background

Wilms’ tumor is an embryonal neoplasm of the kidney that accounts for approximately 6 % of all childhood tumors. The chemokine CXCL12 (C-X-C chemokine ligand 12) and its ligand CXCR4 (C-X-C chemokine receptor type 4) are involved in the development of several organs, including the kidney, and are also associated with tumor growth and metastasis. FOXP3 (forkhead transcription factor 3) was initially described as a marker for regulatory T cells; however, its expression in several types of tumor cells has already been described and may have prognostic significance. The aim of the present study was to analyze rs3761548 and rs2232365 FOXP3 polymorphisms, as well as evaluate rs1801157 CXCL12 polymorphism in Wilms’ tumor samples.

Methods

Polymorphisms were evaluated in 32 patients and 78 neoplasia-free controls. Genotypes of rs1801157 were determined using PCR-restriction fragment length polymorphism (PCR-RFLP) method, and genotypes of rs2232365 and rs3761548 were determined using allele-specific PCR (AS-PCR).

Results

The case-control study indicated a significant association for allele A carriers of rs1801157 polymorphism in relation to Wilms’ tumor susceptibility (OR = 5.261; 95 % CI 2.156 to 12.84; p = 0.0002). The opposite was observed in male carriers of G allele for rs2232365 polymorphism (OR 0.1164; 95 % CI 0.0227 to 0.5954; p = 0.0091) or when male and female subjects were analyzed (OR = 0.1304; 95 % CI 0.05013 to 0.3394; p < 0.0001).

Conclusions

All in all, these markers may contribute to this neoplasia susceptibility and progression; however, further studies are needed to real clarify their role in Wilms’ tumor pathogenesis.

Role of CXCL12 and CXCR4 in normal cerebellar development and medulloblastoma

Chemokines and its receptors have significant impact on physiological and pathological processes and studies concerning their association with tumor biology are subject of great interest in scientific community. CXCL12/CXCR4 axis has been widely studied due to its significant role in tumor microenvironment, but it is also important to development and maintenance of tissues and organs, for example, in the brain and cerebellum. Studies have demonstrated that CXCL12 and CXCR4 are required for normal cerebellar development and that dysfunction in this pathway may be involved with medulloblastoma pathogenesis. In this context, a new molecular subgroup has been suggested based on the importance of the association between CXCR4 overexpression and sonic hedgehog subgroup. Treatment using CXCR4 antagonists showed significant results, evidencing the important role and possible therapeutic capacity of CXCR4 in MB. This review summarizes studies on MB cell biology, focusing on a chemokine-receptor axis, CXCL12/CXCR4, that may have implications for treatment strategies once it can improve life expectancy and reduce neurocognitive sequelae of patients with this neoplasia.