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Breast cancer is the most common type of cancer among women; every year, millions of new cases are detected worldwide, and the cases increase dramatically. Despite the fact that most of the cases are caused by non-genetic factors, hereditary and familial breast cancer also contribute and are considered risk factors that are responsible for about 20% of the cases. The present study aimed to be the first study to investigate the frequency of hereditary breast cancer caused by the high penetrance genes BReast CAncer gene 1 (BRCA1) and BReast CAncer gene 2 (BRCA2) using net generation sequencing (NGS) among Iraqi Kurdish women in Erbil province. Also, investigate several important parameters that some of them have studied for the first time among Kurdish breast cancer patients in Erbil, Iraq.

The present study included 150 participants who were already diagnosed with breast cancer and registered at Nanakali Hospital for Blood Diseases and Cancer, Erbil, Iraq. For mutation analysis and variant detection, 70 participants were selected for NGS. Samples underwent DNA extraction, estimation of the extracted DNA, polymerase chain reaction (PCR) for amplification of all exomes of the BRCA1 and BRCA2 genes, and NGS for sequencing of all coding regions (exomes) through (Illumina Inc., San Diego, CA). Results of NGS obtained in different formats (BAM, BAI, VCF, and FASTA) files. Variant viewing and detection were carried out through the Integrative Genomic Viewer (IGV) and MutationTaster websites. Finally, for interpretation of the clinical significance of the variants, different databases were used, including mainly: NCBI/ClinVar, BRCAExchange, ENIGMA, gnomAD, and COSMIC.

Many variants were detected on these two genes, variants in intronic regions were neglected (except one on BRCA2 that was not benign). At the end, 42 variants were included in the present study, 20 (47.6%) on BRCA1 and 22 (52.4%) on BRCA2. Regarding the clinical significance of the variants, 9 (21.4%) of them were clinically significant. On BRCA1, 4 (9.5%) pathogenic variants were detected (c.3607C>T, c.3544C>T, c.224_227delAAAG, c.68_69del), while on BRCA2, 2 (4.76%) pathogenic variants (c.100G>T, c.1813delA), 2 (4.76%) conflict interpretations of pathogenicity (c.3318C>G, c.1909+12delT), and 1 (2.38%) variant of uncertain significance (c.6966G>T) were detected. Also, 29 (69%) other benign variants were detected on these two genes.

An important finding of the present study was the detection of four new variants, three on the BRCA1 gene (c.463dupC, c.3190A>C, c.981del) and one on the BRCA2 gene (c.3787A>G). Those exact variants were not reported in any databases or articles before. Those new variants were submitted to NCBI/ClinVar, and unique accession numbers were obtained for each of them (SCV005196609, SCV005199865, SCV005199845, SCV005196610), respectively. Detecting new variants on these two genes is popular, especially among low- and middle-income countries, where little or no studies have been done among those populations.

Besides the molecular part, several other important parameters were investigated in the present study, including 150 participants. The mean age at the time of diagnosis with breast cancer was 49.5 years of age, with highly significant differences between the age groups (P<0.0001). The level of awareness by assessing previous knowledge about breast cancer was very low; 120 (80%), had no previous information about breast cancer, and the rest had simple knowledge about different aspects of the disease (P<0.0001). Most of the participants, 131 (87.3%) didn’t undergo any pre-tests before being diagnosed, and the rest underwent a few attempts or just once during their lifetime (P<0.0001). About half of the cases 72 (48%) were detected at advanced stages (stages III and IV), followed by stage I, then stage II (P<0.0001).

Many participants 103 (68.7%) indicated that the cases were observed by the patients themselves (P<0.0001), either by feeling a tumor or pain under the armpit. Despite the fact that cancer is known to be a silent disease, especially in its early stages, more than half 89 (59.3%) of the cases stated that they experienced some signs before the disease was detected; the most popular signs were swelling of the breast, while a few cases felt some pain, vomiting, stiffness of the breast, a shortage in breathing, and finally abnormal stuns in the breath and discharges of liquids, seen rarely (P<0.0001). For family history, 49 (32.7%) of the patients had relatives with breast cancer (P<0.0001). Regarding breast removing surgery, 62 (41.3%) already underwent mastectomy (P<0.04); among the rest of them, 73 (82.9%) stated they would take the choice of mastectomy if needed and recommended in the future.

Regarding the results of the psychological impact, 118 (78.7%) stated that the disease had a bad impact on their lives (P<0.0000.); most of them suffered from depression, and the quality of their sleep lowered dramatically after being diagnosed with cancer. For receiving sufficient information about their status, more than one-third, 53 (35.3%) of the participants stated that they were either little informed or not informed by the physician (P<0.0001). Regarding family support, 140 (93.3%) of them stated that they received good family, relatives, and friends’ support (P<0.0001). The majority 148 (98.7%) were taking one or two types of medications; chemotherapy was the most popular 129 (86%), followed by mastectomy (P<0.0001).