Germline ATM mutational analysis in BRCA1/BRCA2 negative hereditary breast cancer families by MALDI-TOF mass spectrometry

Abstract

Biallelic inactivation of ATM gene causes the rare autosomal recessive disorder Ataxia-telangiectasia (A-T). Female relatives of A-T patients have a two-fold higher risk of developing breast cancer (BC) compared with the general population. ATM mutation carrier identification is laborious and expensive, therefore, a more rapid and directed strategy for ATM mutation profiling is needed. We designed a case-control study to determine the prevalence of 32 known ATM mutations causing A-T in Spanish population in 323 BRCA1/BRCA2 negative hereditary breast cancer (HBC) cases and 625 matched Spanish controls. For the detection of the 32 ATM mutations we used the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technique. We identified one patient carrier of the c.8264_8268delATAAG ATM mutation. This mutation was not found in the 625 controls. These results suggest a low frequency of these 32 A-T causing mutations in the HBC cases in our population. Further case-control studies analyzing the entire coding and flanking sequences of the ATM gene are warranted in Spanish BC patients to know its implication in BC predisposition.

ATM gene mutations in sporadic breast cancer patients from Brazil

“…Overall, 7% of the patient population had ATM gene alterations classified as potential mutations, with the majority being missense variants. Low penetrance, potentially deleterious ATM missense variants, which were associated with an increased risk for breast cancer, have been found in other breast cancer populations (Scott et al 2002 ; Thorstenson et al 2003 ; Graña et al 2011 ). Using SIFT and PolyPhen tools to predict the possible impact of the amino acid changes on the ATM function, we found 4 of the 6 variants identified only in breast cancer patients could be classified as potentially deleterious mutations that might impair ATM function, suggesting a causality to the disease.…”

“…Epidemiological studies have suggested that A-T heterozygous individuals are at increased relative risk for cancer, especially breast cancer (Thompson et al 2005 ; Ahmed and Rahman 2006 ). Hence, several studies have investigated the frequency, relative risk, and clinical significance of ATM mutations in breast cancer patients (Ahmed and Rahman 2006 ; Tavtigian et al 2009 ; Graña et al 2011 ). In the present study, we examined DNA from a series of 100 breast cancer patients without a family history of breast cancer and 100 healthy individuals for ATM gene mutations.…”

Genetics of breast cancer in African populations: a literature review

“…The ethnic similarity between the different regions of Europe and Africa can guide African scientists to well investigate the genes involved in BC. For instance, research in North Africa should explore other genes, such as GSTM1 , GSTT1 found in Portugal [ 89 ] and PALB2 , ATM , TNFRSF11A found in Spain [ 80 , 90 , 91 ].…”

Applying and testing the conveniently optimized enzyme mismatch cleavage method to clinical DNA diagnosis

“…Although DHPLC could achieve high sensitivity, this system is relatively low throughput and it requires time-consuming optimization of the conditions for each DNA sequence to obtain the maximum sensitivity [2,4]. Another technology is based on mass spectrometry: matrix-assisted laser desorption ionization-timeof-flight mass spectrometry (MALDI-TOF MS) [6,7]. Mutations become apparent peaks in the spectra in comparison with the wild type.…”

“…to obtain maximum sensitivity researchers must try several different gel running conditions and short (b300 bp) PCR products [1][2][3]. On the other hand, recently developed methods such as denaturing high-performance liquid chromatography (DHPLC) [4,5], Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) [6,7] or next-generation sequencing [8] require totally new instruments and are consequently not becoming popular because of the high initial cost of these machines. Therefore, amplifying every coding exon of disease causative genes by PCR and performing direct sequencing on all of them is still a gold standard strategy of molecular diagnosis in many laboratories, even though this approach is time-consuming and expensive.…”