Molecular-Genetic Portrait of Breast Cancer with Triple Negative Phenotype

Association between Toll-like receptor 2 rs4696483 and rs1898830 polymorphisms and the risk of triple-negative breast cancer

PURPOSE

Breast cancer (BC) is heterogeneous in clinical manifestation, of which the triple-negative (TNBC) subtype is the most aggressive. This study examines the associations between Toll-Like Receptor (TLR)-2 polymorphisms and the susceptibility to BC and TNBC.

METHODS

Genotyping of TLR-2 rs1898830 and rs4696483 polymorphisms was done by real-time PCR in 488 women with BC (130 TNBC, 358 non-TNBC) and 476 cancer-free control women.

RESULTS

The minor allele frequency (MAF) of rs4696483 was significantly lower in BC cases compared to controls, and significantly lower frequencies of rs4696483 C/T and higher frequencies of rs1898830 G/G genotypes were seen in BC cases. Significantly higher MAF of rs4696483 and higher C/T and T/T rs4696483 genotypes frequencies were seen in TNBC than in non-TNBC cases. Considering the prevalent AC haplotype as a reference, 2-locus TLR-2 haplotype analysis did not identify any 2-locus TLR-2 haplotype associated with an altered risk of BC or TNBC. Positive associations of rs1898830 and rs4966483 were seen with the histological type in TNBC and negatively with distant metastasis and HR status in TNBC and non-TNBC rs1898830 carriers. In addition, rs4696483 was positively correlated with hormonotherapy and surgery in non-TNBC cases, while rs1898830 was negatively associated with hormonotherapy. Furthermore, rs1898830 was negatively and positively correlated with BMI in TNBC and TNBC cases, respectively, but positively with Ki-67 status.

CONCLUSIONS

Our study highlights the association between TLR-2 genetic polymorphisms and BC and TNBC susceptibility, suggesting these variants' diagnostic/prognostic capacity in BC patients and patient subgroups.

Novel Association of IGF2BP2 Gene Variants With Altered Risk of Breast Cancer and as Potential Molecular Biomarker of Triple Negative Breast Cancer

BACKGROUND

Several studies documented that insulin-like growth factor-2 mRNA-binding protein 2 (IGF2BP2) contributes to carcinogenesis, and 1 report documented the association of IGF2BP2 rs4402960 with increased risk of breast cancer (BC). This study investigated the association of rs4402960 and rs1470579 IGF2BP2 variants with BC and triple negative BC (TNBC).

MATERIALS AND METHODS

This case-control study included 488 BC patients comprising 130 TNBC and 358 non-TNBC patients, and 476 cancer-free controls. Genomic DNA was obtained from peripheral venous blood, and genotyping was done by allelic exclusion method on real-time PCR.

RESULTS

The rs440960, but not rs1470579, minor allele was significantly associated with BC, and significantly higher rs4402960 T/T genotype frequency was noted in BC patients than controls; the distribution of rs1470579 genotypes were comparable between BC patients and controls. In contrast, significantly lower rs1470579 minor allele frequency, and reduced rs1470579 A/C and C/C, and rs4402960 T/T genotype frequencies were seen in TNBC cases. Among TNBC cases, rs4402960 and rs1470579 correlated with menses pattern, histological type, breastfeeding, oral contraceptive use and hormonotherapy. Among non-TNBC patients, and rs1470579 correlated significantly with breast feeding, oral contraceptive use, hormonotherapy, and nodal status; rs4402960 also correlated with menses pattern. Two-locus (rs440960-rs1470579) haplotype analysis confirmed the positive association of TC, and negative association of GC and TA haplotypes with BC, while TC and GC haplotypes were negatively associated with TNBC.

CONCLUSION

Whereas rs440960 was positively associated with BC, both rs4402960 and rs1470579 were negatively associated with TNBC, suggesting potential diagnostic/prognostic role in BC and its complications.

Vav1 Selectively Down-Regulates Akt2 through miR-29b in Certain Breast Tumors with Triple Negative Phenotype

Triple negative breast cancer (TNBC) represents the most aggressive breast tumor, showing a high intrinsic variability in terms of both histopathological features and response to therapies. Blocking the Akt signaling pathway is a well-studied approach in the treatment of aggressive breast tumors. The high homology among the Akt isoforms and their distinct, and possibly opposite, oncogenic functions made it difficult to develop effective drugs. Here we investigated the role of Vav1 as a potential down-regulator of individual Akt isozymes. We revealed that the over-expression of Vav1 in triple negative MDA-MB-231 cells reduced only the Akt2 isoform, acting at the post-transcriptional level through the up-modulation of miR-29b. The Vav1/miR-29b dependent decrease in Akt2 was correlated with a reduced lung colonization of circulating MDA-MB-231 cells. In cell lines established from PDX, the Vav1 induced down-modulation of Akt2 is strongly dependent on miR-29b and occurs only in some TNBC tumors. These findings may contribute to better classify breast tumors having the triple negative phenotype, and suggest that the activation of the Vav1/miR-29b axis, precisely regulating the amount of an Akt isozyme crucial for tumor dissemination, could have great potential for driving more accurate therapies to TNBCs, often not eligible or resistant to treatments.

MiR-150-5p Overexpression in Triple-Negative Breast Cancer Contributes to the In Vitro Aggressiveness of This Breast Cancer Subtype

Simple Summary

Triple-negative breast cancer (TNBC) is a clinically aggressive type of breast cancer. MicroRNAs (miRNAs) are small molecules that regulate the expression of genes involved in tumor cell signaling. The miR-150-5p is frequently deregulated in cancer, with expression and mode of action varying according to the cancer type. In this study, we investigated the expression levels of miR-150-5p in TNBC, its association with clinical and pathological features of patients, and its role in modulating TNBC cell proliferation, migration, and drug resistance. Our results suggest that miR-150-5p is highly expressed in TNBC and that miR-150-5p expression levels are associated with tumor grade, patient survival, and ethnicity. Our findings also indicate that miR-150-5p contributes to the aggressive phenotypes of TNBC cells in vitro.

Abstract

MiR-150-5p is frequently deregulated in cancer, with expression and mode of action varying according to the tumor type. Here, we investigated the expression levels and role of miR-150-5p in the aggressive breast cancer subtype triple-negative breast cancer (TNBC). MiR-150-5p expression levels were analyzed in tissue samples from 113 patients with invasive breast cancer (56 TNBC and 57 non-TNBC) and 41 adjacent non-tumor tissues (ANT). Overexpression of miR-150-5p was observed in tumor tissues compared with ANT tissues and in TNBC compared with non-TNBC tissues. MiR-150-5p expression levels were significantly associated with high tumor grades and the Caucasian ethnicity. Interestingly, high miR-150-5p levels were associated with prolonged overall survival. Manipulation of miR-150-5p expression in TNBC cells modulated cell proliferation, clonogenicity, migration, and drug resistance. Manipulation of miR-150-5p expression also resulted in altered expression of its mRNA targets, including epithelial-to-mesenchymal transition markers, MYB, and members of the SRC pathway. These findings suggest that miR-150-5p is overexpressed in TNBC and contributes to the aggressiveness of TNBC cells in vitro.