Segmental Duplications as a Complement Strategy to Short Tandem Repeats in the Prenatal Diagnosis of Down Syndrome.

BACKGROUND: Quantitative fluorescence-polymerase chain reaction (QF-PCR) is an inexpensive and accurate method for the prenatal diagnosis of aneuploidies that applies short tandem repeats (STRs) as a chromosome-specific marker. Despite its apparent advantages, QF-PCR is not applicable in all cases due to the presence of uninformative STRs. This study was carried out to investigate the efficiency of a method based on applying segmental duplications (SDs) in conjunction with STRs as an alternative to stand-alone STR-based QF-PCR for the diagnosis of Down syndrome. METHODS: Fifty amniotic fluid samples from pregnant women carrying Down syndrome fetuses, 9 amniotic fluid samples with 1 or without any informative STR marker (inconclusive), and 100 normal samples were selected from Shiraz, Iran, between October 2015 and December 2016. Analysis was done using an in-house STR-SD-based multiplex QF-PCR and the results were compared. Statistical analysis was performed using MedCalc, version 14. RESULTS: All the normal, Down syndrome, and inconclusive samples were accurately identified by the STR-SD-based multiplex QF-PCR, yielding 100% sensitivity and 100% specificity. Karyotype analysis confirmed all the cases with normal or trisomic results. CONCLUSION: The STR-SD-based multiplex QF-PCR correctly identified all the normal and trisomy 21 samples regardless of the absence of informative STR markers. The STR-SD-based multiplex QF-PCR is a feasible and particularly useful assay in populations with a high prevalence of homozygote STR markers.

The First Case of a Small Supernumerary Marker Chromosome 18 in a Klinefelter Fetus: A Case Report.

Small supernumerary marker chromosomes (sSMCs), or markers, are abnormal chromosomal fragments that can be hereditary or de novo. Despite the importance of sSMCs diagnosis, de novo sSMCs are rarely detected during the prenatal diagnosis process. Usually, prenatally diagnosed de novo sSMCs cannot be correlated with a particular phenotype without knowing their chromosomal origin and content; therefore, molecular cytogenetic techniques are applied to achieve this goal. The present study aimed to characterize an sSMC in a case of Klinefelter syndrome using an in-house microsatellite analysis method and fluorescent in situ hybridization (FISH) technique. Amniotic fluid was collected from a pregnant woman who was considered to have risk factors for trisomy higher than the screening cut-off. Karyotype analysis was followed by the amplification of different microsatellite loci and FISH technique. Karyotype analysis identified a fetus with an extra X chromosome and also an sSMC with unknown identity. Further investigation of the parents showed that the sSMC is de novo. Microsatellite amplification by quantitative fluorescent PCR (QF-PCR) and FISH analysis showed that the sSMC is a derivative of chromosome 18. Eventually, the patient decided to terminate the pregnancy. Here, the first case of the coincidence of sSMC 18 in a Klinefelter fetus is reported.

Expression levels of breast cancer-related GAS5 and LSINCT5 lncRNAs in cancer-free breast tissue: Molecular associations with age at menarche and obesity.

Long noncoding RNAs (lncRNAs) constitute a major class of the human transcriptome which play crucial roles in the key biological processes of both normal and malignant breast cells. Although the aberrant expression of lncRNAs has been well-documented in breast cancer (BC), little is currently known about the association between their expression levels in the breast tissue of healthy women and BC risk factors, especially the reproductive or demographic characteristics that are among the most well-known BC risk modifiers. This study was an attempt to investigate the correlation between the expression levels of 2 breast cancer-related lncRNAs, including GAS5 and LSINCT5, and reproductive and demographic characteristics in 145 normal breast tissues that were obtained from women without breast cancer undergoing cosmetic surgery. Total RNA was extracted from fresh normal breast tissues, and the expression level of target lncRNAs was quantified using real-time qPCR. Differences in the mean normalized gene expression among the subgroups of different variables were analyzed. The expression levels of both genes was lower in the overweight-obese (BMI ≥ 25) subgroup than that in the normal BMI (BMI < 25) subgroup (GAS5 P = .019, LSINCT5 P = .036). Moreover, the expression level of GAS5 was negatively correlated with BMI (r: -.170, P: .041). The expression level of GAS5 was higher in women with late menarche (>13 years) than that with early menarche (≤13 years; P = .017). These findings may assist to obtain insights into the molecular mechanisms through which the reproductive or obesity-related estrogen changes contribute to the breast carcinogenesis. In conclusion, this study presents the first evidence for the presence of a link between the lncRNA expression and the reproductive or obesity related factors in the breast tissue of healthy women.

Expression and clinicopathological significance of AOC4P, PRNCR1, and PCAT1 lncRNAs in breast cancer.

Long none coding RNAs (lncRNAs) AOC4P, PRNCR1, and PCAT-1 are dysregulated in various types of malignancies. However, their expression and clinicopathological significances are uncertain in breast cancer (BC). Quantitative real-time polymerase chain reaction (RT- qPCR) was used to measure the expression levels of the selected lncRNAs in tumor tissues obtained from 50 BC patients compared to the normal adjacent tissues (NATs) and 50 clinically healthy normal tissues. Our results revealed a significant downregulation of AOC4P, however, upregulated PRNCR1 and PCAT1 were found in tumor tissues compared to NATs and clinically healthy normal tissues (P < 0.05). Interestingly, remarkable decreased expression of AOC4P was observed in NATs than clinically healthy normal tissues. Dysregulation of the lncRNAs was correlated with worse outcomes of patients. Furthermore, our data showed that the altered expression levels of lncRNAs AOC4P, PRNCR1, and PCAT1 might be occurred through the function of demographic and reproductive variables. Taken together, the altered regulation of AOC4P, PRNCR1, and PCAT1 may highlight their crucial roles in BC development and pathogenesis. Our findings also proposed demographic and reproductive variables as risk factors in BC through the possible influence on the expression of the studied lncRNAs. Nevertheless, further explorations are required to elucidate the more detailed functions of these lncRNAs in BC.

A link between expression level of long-non-coding RNA ZFAS1 in breast tissue of healthy women and obesity.

BACKGROUND: Epidemiological and experimental literature indicates that the risk of breast cancer incidence is strongly linked to hormone-dependent factors, including reproductive history and obesity. However, the molecular mechanisms underlying the association between these factors and breast cancer risk are poorly understood. The aim of this study, therefore, was to determine whether obesity and reproductive history are associated with expression levels of two breast cancer-related long non-coding RNAs (lncRNAs), namely ZFAS1 and SRA1 in cancer-free breast tissues of women. METHODS: In the current research, 145 healthy women were recruited, and the quantitative expression levels of the two lncRNAs were determined through qPCR assay after gathering the mammoplasty breast tissue samples. RESULTS: It was found that women with body mass index (BMI)≥30 kg/m2 and BMI 25-29 kg/m2 show a low expression of ZFAS1 compared to the BMI<25 kg/m2 (P=0.031 and P=0.027, respectively). Then, the correlation analysis disclosed a negative correlation of ZFAS1 low expression with increasing BMI (r=-0.194, P=0.019). Interestingly, this analysis demonstrated a negative correlation between low expression of the ZFAS1 and high BMI in women with menarche age below 14 (r=-221; P=0.028). Lastly, it was also revealed that there was a negative association of the low expression level of ZFAS1 with increasing BMI in women through regression models (B=-0.048, P=0.019). CONCLUSIONS: These findings suggest interesting clues about the links between high BMI and the expression levels of ZFAS1 in non-diseased breasts that may help us better understand the underlying mechanisms through which obesity contributes to breast carcinogenesis. However, such results need more validations in future research.