Clinicopathological and Molecular Study of Triple-Negative Breast Cancer in Algerian Patients

Genomic characterization reveals distinct mutational landscapes and therapeutic implications between different molecular subtypes of triple-negative breast cancer

Triple-negative breast cancer (TNBC) has high heterogeneity, poor prognosis, and limited treatment success. Recently, an immunohistochemistry-based surrogate classification for the "Fudan University Shanghai Cancer Center (FUSCC) subtyping" has been developed and is considered more suitable for clinical application. Seventy-one paraffin-embedded sections of surgically resected TNBC were classified into four molecular subtypes using the IHC-based surrogate classification. Genomic analysis was performed by targeted next-generation sequencing and the specificity of the subtypes was explored by bioinformatics, including survival analysis, multivariate Cox regression, pathway enrichment, Pyclone analysis, mutational signature analysis and PHIAL analysis. AKT1 and BRCA1 mutations were identified as independent prognostic factors in TNBC. TNBC molecular subtypes encompass distinct genomic landscapes that show specific heterogeneities. The luminal androgen receptor (LAR) subtype was associated with mutations in PIK3CA and PI3K pathways, which are potentially sensitive to PI3K pathway inhibitors. The basal-like immune-suppressed (BLIS) subtype was characterized by high genomic instability and the specific possession of signature 19 while patients in the immunomodulatory (IM) subtype belonged to the PD-L1 ≥ 1% subgroup with enrichment in Notch signaling, suggesting a possible benefit of immune checkpoint inhibitors and Notch inhibitors. Moreover, mesenchymal-like (MES) tumors displayed enrichment in the receptor tyrosine kinase (RTK)-RAS pathway and potential sensitivity to RTK pathway inhibitors. The findings suggest potential treatment targets and prognostic factors, indicating the possibility of TNBC stratified therapy in the future.

Mutational spectrum of BRCA1/2 genes in Moroccan patients with hereditary breast and/or ovarian cancer, and review of BRCA mutations in the MENA region

PURPOSE

Breast cancer (BC) is the most common form of female cancer around the world. BC is mostly sporadic, and rarely hereditary. These hereditary forms are mostly BRCA1- and BRCA2-associated hereditary breast and ovarian cancer syndrome. BRCA1 and BRCA2 genes are large and had some recurrent mutations specific to some populations. Through this work we analyze the most recurrent mutations in Moroccan population and compared them to a large review of other BRCA1/2 spectrum mutations in the MENA region.

METHODS

We report in this work a series of 163 unrelated patients (the largest series of Moroccan patients) with familial breast and/or ovarian cancer, selected among patients referred to our oncogenetic outpatient clinic, from 2006 to 2021. To identify genetic variants in these two genes, different genetic analysis strategies have been carried out, using Sanger Sequencing DNA or Target Panel Sequencing.

RESULTS

Pathogenic variants were identified in 27.6% of patients. The most frequent mutation identified in our patients was the c.1310_1313delAAGA, BRCA2 (33%), and three other mutations seem more frequent in the Moroccan population (33%) of all reported patients: c.798_799delTT, BRCA1; and c.3279delC, BRCA1; and c.7234_7235insG in BRCA2 gene.

CONCLUSION

Through this work, we emphasize the importance of screening for BRCA1 and BRCA2 recurrent mutations in Moroccan patients. Other MENA (MENA: English-language acronym referring to the Middle East and North Africa region) countries had also some recurrent BRCA mutations, which will allow a fast and unexpensive first line genetic analysis and a precise molecular diagnosis. This will allow an adapted follow-up of the patients and a pre-symptomatic diagnosis of their relatives.

Expression of PD-L1 and BRCA1 in Triple-Negative Breast Cancer Patients and Relationship with Clinicopathological Characteristics

Objective

To study the expression of programmed cell death ligand-1 (PD-L1) and breast cancer susceptibility gene 1 (BRCA1) in triple-negative breast cancer (TNBC) patients and analyze their relationship with clinicopathological characteristics.

Methods

76 TNBC tissues were collected as the research object, while 60 adjacent tissues were used as controls. All patients underwent surgical treatment, and the expression of PD-L1 and BRCA1 in cancer tissues and adjacent tissues was detected by immunohistochemistry. At the same time, the relationship between PD-L1, BRCA1, and clinicopathological characteristics of patients with TNBC (including patient age, menopausal status, tumor size, lymph node metastasis, histological grade, Ki-67 expression, and p53 expression) were analyzed by univariate and logistic multivariate analysis.

Results

The positive expression rate of PD-L1 in the TNBC group was 64.47%, which was higher than the control group by 41.67%. The positive expression rate of BRCA1 was 27.63%, which was lower than the control group by 48.33%. PD-L1 expression has no significant relationship with age, menopausal status, and p53 expression in TNBC patients. TNBC patients with tumors ≥2 cm, histological grade III, lymph node metastasis, and Ki-67 expression ≥20% had higher PD-L1 positive expression rates. The tumor size, Ki-67 expression, and PD-L1 expression of TNBC patients have independent effects. The expression of BRCA1 has no significant relationship with menopausal status, tumor size, Ki-67 expression, etc. TNBC patients with age <45 years, histological grade I or II, no lymph node metastasis, and high p53 expression positive rate had higher BRCA1 positive expression rate. The age of TNBC patients, p53 expression, and BRCA1 expression have independent effects.

Conclusion

In TNBC cancer tissues, there is a high expression of PD-L1 and low expression of BRAC1. The tumor size, Ki-67 expression, and PD-L1 expression of TNBC patients have independent effects. The age of TNBC patients, p53 expression, and BRCA1 expression have independent effects.

Identification of a novel pathogenic variant in PALB2 and BARD1 genes by a multigene sequencing panel in triple negative breast cancer in Morocco

Pathogenic variants (PVs) in BRCA genes have been mainly associated with an increasing risk of triple negative breast cancer (TNBC). The contribution of PVs in non-BRCA genes to TNBC seems likely since the processing of homologous recombination repair of double-strand DNA breaks involves several genes. Here, we investigate the susceptibility of genetic variation of the BRCA and non-BRCA genes in 30 early-onset Moroccan women with TNBC. Methods: Targeted capture-based next generation sequencing (NGS) method was performed with a multigene panel testing (MGPT) for variant screening. Panel sequencing was performed with genes involved in hereditary predisposition to cancer and candidate genes whose involvement remains unclear using Illumina MiSeq platform. Interpretation was conducted by following the American College of Medical Genetics and Genomics-Association for Molecular Pathology (ACMG-AMP) criteria. Results: PVs were identified in 20% (6/30) of patients with TNBC. Of these, 16.7% (5/30) carried a BRCA PV [10% (3/30) in BRCA1, 6.7% (2/30) in BRCA2] and 6.6% (2/30) carried a non-BRCA PV. The identified PVs in BRCA genes (BRCA1 c.798_799delTT, BRCA1 c.3279delC, BRCA2 c.1310_1313del, and BRCA2 c.1658T>G) have been reported before and were classified as pathogenic. The identified founder PVs BRCA1 c.798_799del and BRCA2 c.1310_1313delAAGA represented 10% (3/30). Our MGPT allowed identification of several sequence variations in most investigated genes, among which we found novel truncating variations in PALB2 and BARD1 genes. The PALB2 c.3290dup and BARD1 c.1333G>T variants are classified as pathogenic. We also identified 42 variants of unknown/uncertain significance (VUS) in 70% (21/30) of patients with TNBC, including 50% (21/42) missense variants. The highest VUS rate was observed in ATM (13%, 4/30). Additionally, 35.7% (15/42) variants initially well-known as benign, likely benign or conflicting interpretations of pathogenicity have been reclassified as VUS according to ACMG-AMP. Conclusions: PALB2 and BARD1 along with BRCA genetic screening could be helpful for a larger proportion of early-onset TNBC in Morocco.

Association of vitamin D deficiency and insulin resistance with breast cancer in premenopausal Algerian women: A cross-sectional study

BACKGROUND

Low 25(OH)D levels are mainly related to breast cancer (BC) risk in postmenopausal women, while the impact of insulin resistance (IR) on BC prognosis is controversial.

OBJECTIVE

Considering the high prevalence of BC in younger Algerian women, this cross-sectional study analyzed whether vitamin D status and IR are biomarkers for breast tumor status in premenopausal women.

METHODS

In 96 women (mean age, 40.96±0.65years) newly diagnosed with BC, tumor status was determined immunohistochemically, classified by molecular subtype, then correlated with body-mass index, total plasma 25(OH)D, insulin and glucose levels and HOMA-IR, using chi², Student t, Spearman and ANOVA tests and multivariate logistic regression.

RESULTS

66 of the 98 patients (68.75%) showed vitamin D deficiency (9.74ng/mL). Overweight and obese patients with HOMA-IR >2.5, positive for HER2 and with high Ki-67 index had the most severe vitamin D deficiency. There was a significant association between vitamin D deficiency, high Ki-67 index (OR, 14.55; 95% CI, 3.43-82.59; p=0.00078) and IR (OR, 4.99; 95% CI, 1.27-24.47; p=0.03), and between IR and HER2-positivity (OR, 3.23; 95% CI, 1.05-10.56; p=0.04).

CONCLUSIONS

Vitamin D deficiency and IR are potential biomarkers for poorer prognosis in BC patients, independently of and/or synergically with high Ki-67 index and HER2-positivity in premenopausal overweight or obese women. The potential relationship of vitamin D receptor gene expression with breast cancer survival in Algerian patients will be investigated in a large cohort.

The hispanic landscape of triple negative breast cancer

Triple-negative breast cancer (TNBC) is a heterogeneous and complex disease characterized by the absence of immunohistochemical expression of estrogen receptor, progesterone receptor and HER2. These breast tumors present an aggressive biology and offer few opportunities to be treated with targeted therapy resulting in bad disease outcomes. The epidemiology of TNBC is intriguing where the understanding of its biology has progressed quickly. One of the peculiarities of this type of cancer is a high prevalence in Afrodescendants and Hispanic patients compared to Caucasian women. In this review we describe some features of TNBC, focusing in the Hispanic population, such as epidemiological, clinicopathological features and molecular features and the correlation between TNBC prevalence and the human development index.

Contribution of BRCA1 and BRCA2 germline mutations to early onset breast cancer: a series from north of Morocco

BACKGROUND

To date, the contribution of BRCA1/2 mutations in Moroccan early onset breast cancer patients remains unknown. Here we assess these genetic alterations for the first time in a cohort from North of Morocco.

METHODS

Thirty-three patients diagnosed with breast cancer at the age of ≤40 years were recruited irrespective of breast and/or ovarian cancer family history. Coding regions and intron-exon boundaries of BRCA1 and BRCA2 genes were sequenced from peripheral blood DNA using Ion Proton (Thermo Fisher Scientific) next generation sequencing platform.

RESULTS

Overall, five BRCA germline mutations were identified (15.1%). The frequency of mutations among patients with family history of breast cancer was 16.7%. Three mutations were found in BRCA1 (9%) and two within the BRCA2 gene (6%). These are three frameshift mutations (c.798_799del, c.2125_2126insA, c.5116_5119delAATA), one missense (c.116G > A) and one nonsense mutation (c.289G > T). The mutation c.5116_5119delAATA has a founder effect in North Africa. Moreover, one variant of unknown significance was identified in BRCA2 (c.4090A > G). Most BRCA mutations carriers (80%) had no family history of breast cancer.

CONCLUSION

Our data do not support the hypothesis that BRCA mutations alone explain the higher frequency of breast cancer in Moroccan young women. The young age (≤40 years) for breast cancer diagnosis seems to be strongly predictive of BRCA mutation status in Moroccan patients. These results will help in decision making with regard to genetic counseling and testing in the national scale.

Clinicopathological, Treatment and Event-Free Survival Characteristics in a Moroccan Population of Triple-Negative Breast Cancer

Introduction:

Triple-negative breast cancer (TNBC) is a group of breast carcinoma characterized by the lack of expression of estrogen and progesterone hormone receptors (ER, PgR) and HER2. This form is also characterized by its aggressiveness, a low survival rate, and the absence of targeted therapies. This study was planned to evaluate the clinical features, treatment, and prognosis characteristics of TNBC in a population of Moroccan patients.

Methods:

In this retrospective study, a total of 905 patients diagnosed with breast cancer at the National Institute of Oncology in Rabat, Morocco, have been included. Based on molecular subtype, patients were divided into 2 categories: TNBC and non-TNBC patients. Data were recorded from patients’ medical files and analyzed using SPSS 13.0 software (IBM).

Results:

Overall, 17% of the patients had TNBC. At diagnosis, the median age of TNBC cases was 47 years, with extreme ages of 40 and 55 years. The median follow-up time was 30 months (10-53 months) and the 3-year survival rate was 76%. No significant difference was observed among the patients in terms of age at diagnosis, age at menarche, age at the time of first birth, nulliparity, oral contraception, and family history of breast cancer. Menopausal status and the number of pregnancy were significantly higher in the non-TNBC group. The percentage of grade 3 (G3) tumors was higher in the TNBC group (P < .001). Using neoadjuvant, adjuvant chemotherapy and radiotherapy, a net benefit in the event-free survival was registered for the 2 groups.

Conclusions:

This retrospective study was very informative and showed that women with TNBC had a less favorable prognosis than non-TNBC cases. Clinical data demonstrated that risk factors including age, premenopausal status, parity, hormonal contraceptive use, advanced disease, and a high histologic grade were independently associated with TNBC. However, large tumors and high Scarff-Bloom and Richardson grade prevail in TNBC cases with a higher incidence of lymph node metastases.