ovarian cancer ( oc ) affects approximately 1 out of 70 women during their lifetime and is regarded as the most lethal gynaecological malignancy . early ovarian cancer does not usually cause symptoms ; therefore it can be detected only through prophylactic medical check . furthermore , even the combination of sophisticated technologies , such as ultrasound examination , magnetic resonance imaging , and ca-125 antigen measurement , does not fully guarantee timely oc diagnosis [ 1 - 3 ] . a significant portion of oc cases arise due to the presence of a germline mutation in the brca1 or brca2 gene . estimates of occurrence of brca mutations in unselected oc cases vary from 3% to 35% ( reviewed in ) . surprisingly , the occurrence of brca defects in random series of oc is similar to that observed in high - risk categories of breast cancer ( bc ) , such as familial and/or early - onset and/or bilateral cases of the disease . complete analysis of brca1 and brca2 genes can not be used yet on a large scale due to the high cost of appropriate laboratory procedures . fortunately , in some ethnic groups and geographic regions the brca mutation spectrum is limited to a small number of so - called founder mutations . for example , only a few simple pcr tests allow most of the brca carriers in israel , iceland , poland , russia , etc to be revealed . one of these founder mutations is brca1 4153dela , which was originally described in russian cancer families . this mutation also occurs in poland , latvia , lithuania and belarus [ 7 - 13 ] . some evidence suggest that this mutation is more associated with ovarian than with breast cancer . in particular , the initial study of gayther et al . , which identified three 4153dela mutations in 19 families , furthermore , a series of investigations performed by lubinski and associates demonstrated a noticeable occurrence of brca1 4153dela in ovarian but not in breast cancer patients . for example , a study of unselected polish patient series has revealed 8/364 ( 2.2% ) carriers in oc , but only 1/2012 ( 0.05% ) in bc cases . we have recently tested 302 breast cancer patients characterized by family history and/or early - onset and/or bilaterality , and detected 3 ( 1% ) 4153dela allele carriers [ sokolenko et al . , manuscript submitted ] . based on the apparent russian origin of this mutation   as well as on its probable specificity towards oc predisposition , we hypothesized that unselected ovarian cancer cases from russia will be characterized by highly elevated occurrence of the 4153dela variant . briefly , tissue sections were deparaffinized in 2 changes of xylene , and then boiled for 5 min . in 100 l of the lysis buffer ( 10 mm tris - hcl , ph 8.3 ; 1 mm edta ; 0.5% np-40 , 0.5% tween 20 ) . proteinase k was subsequently added up to the concentration of 500 g / ml . protein digestion was done overnight at 60c . next , the tissue lysates were boiled again in order to inactivate proteinase k. finally , samples were diluted to 1:10 with water in order to decrease the concentration of pcr inhibitors . clinical characteristics of ovarian carcinoma patients brca1 4153dela was detected using sybr green based real - time allele - specific pcr . primers were 5'-gactgcaaatacaaacaccca-3 ' ( common ) , 5'-agcccgttcctctttcttc-3 ' ( specific for the wild - type allele ) , and 5'-agcccgttcctctttctca-3 ' ( specific for the 4153dela mutation ) . , 72c for 60 sec . ) in the icycler iq real time detection system ( bio - rad ) . 10 l of pcr cocktail included 1 l diluted archival tissue lysate , 1 unit heat - activated taq dna polymerase , 1  pcr buffer ( ph 8.3 ) , 2.5 mm mgcl2 , 200 m dntp , 0.5 m each primer , and 0.5sybr green i. the specificity of the 134-bp pcr product was confirmed by melting curve analysis . in order to control the accuracy of the real - time genotyping , a conventional gel - based allele - specific pcr ( 35 cycles in the same conditions ) was applied to all mutation - positive samples as well as to some randomly selected mutation - negative dna specimens . briefly , tissue sections were deparaffinized in 2 changes of xylene , and then boiled for 5 min . in 100 l of the lysis buffer ( 10 mm tris - hcl , ph 8.3 ; 1 mm edta ; 0.5% np-40 , 0.5% tween 20 ) . proteinase k was subsequently added up to the concentration of 500 g / ml . protein digestion was done overnight at 60c . next , the tissue lysates were boiled again in order to inactivate proteinase k. finally , samples were diluted to 1:10 with water in order to decrease the concentration of pcr inhibitors . brca1 4153dela was detected using sybr green based real - time allele - specific pcr . primers were 5'-gactgcaaatacaaacaccca-3 ' ( common ) , 5'-agcccgttcctctttcttc-3 ' ( specific for the wild - type allele ) , and 5'-agcccgttcctctttctca-3 ' ( specific for the 4153dela mutation ) . 10 l of pcr cocktail included 1 l diluted archival tissue lysate , 1 unit heat - activated taq dna polymerase , 1  pcr buffer ( ph 8.3 ) , 2.5 mm mgcl2 , 200 m dntp , 0.5 m each primer , and 0.5sybr green i. the specificity of the 134-bp pcr product was confirmed by melting curve analysis . in order to control the accuracy of the real - time genotyping , a conventional gel - based allele - specific pcr ( 35 cycles in the same conditions ) was applied to all mutation - positive samples as well as to some randomly selected mutation - negative dna specimens . 1 . as seen in this figure , allele - specific pcr allowed reliable discrimination between mutated and wild - type alleles in both real - time and conventional format . brca 4153dela genotyping . both wild - type and mutation - specific primers produce the pcr fragment for the heterozygote ( left ) , while only one product is detected upon the analysis of normal dna sample ( right ) . identical results are obtained by real - time ( top ) and conventional ( bottom ) allele - specific pcr an analysis of 177 unselected ovarian cancer cases allowed only two 4153dela mutation carriers ( 1.1% ) to be revealed . both cases were early onset ( 39 and 42 years , respectively ) , and had identical morphological characteristics ( t3nxm0 , serous histology , grade 3 ) . records on family history in the present data set were incomplete and therefore not considered in the study analysis ; nevertheless , one of the brca1 4153dela carriers reported an ovarian cancer in her grandmother . since the observed frequency of the 4153dela allele was lower than expected , part of the dna samples was genotyped for brca1 5382insc mutation . brca1 5382insc occurs in up to 10% of familial and/or early - onset and/or bilateral breast cancer patients in russia ; therefore it is likely to be frequent in ovarian cancers as well . an analysis of the 5382insc variant was performed as a positive control for 21 oc samples from our series , and 5 mutations ( 23.8% ) were revealed . therefore we conclude that the low frequency of brca1 4153dela is not an artefact of the study design , but reflects the true contribution of this allele in russian ovarian cancer . this study failed to reveal elevated incidence of brca1 4153dela mutation in unselected russian patients suffering from ovarian cancer . brca1 4153dela was detected in several east european countries ; however , its frequency significantly varies even within closely located geographic regions . the uneven distribution of 4153dela allele carriers may reflect a relatively recent origin of this genetic variant . the data obtained in the present study are strikingly similar to the results of the analysis of russian familial and/or early - onset and/or bilateral breast cancer [ sokolenko et al . , manuscript submitted ] . in particular , we observed moderate frequency of brca1 4153dela mutation ( 2/177 ( 1.1% ) for oc and 3/302 ( 1.0% ) for bc ) , but highly elevated occurrence of the brca1 5382insc variant ( 5/21 ( 23.8% ) for oc and 29/302 ( 9.6% ) for bc ) . nonetheless , given the presumably high penetrance of brca1 truncating mutations , even the frequency of 1% in cancer patients seems to be sufficient justification for extended genetic testing . therefore , we believe that brca1 4153dela mutation has to be included in the array of tests aimed at revealing cancer syndrome carriers among subjects of russian origin . in conclusion , this study supports neither the russian origin of brca1 4153dela mutation   nor its selectivity towards ovarian versus breast cancer predisposition . however , the 4153dela variant does make a moderate contribution to breast and ovarian cancer incidence in russia ; thus it has to be considered in clinical practice . this work was supported by intas ( grant 03 - 51 - 4234 ) , rfbr ( grant 05 - 04 - 49774 ) , and the government of moscow ( grant 06 - 15 ) . olga s. yatsuk , olga a. zaitseva and liudmila v. rikunova for their technical assistance .
the brca1 4153dela allele is frequently referred to as the russian founder mutation , as it was initially detected in several cancer families from moscow . 
 our earlier studies have demonstrated 1% occurrence of brca1 4153dela heterozygosity in familial and/or early - onset and/or bilateral russian breast cancer ( bc ) patients . 
 since literature data suggest that the 4153dela variant is more associated with ovarian cancer ( oc ) than with bc , we expected to reveal a highly elevated frequency of this genotype in russian ovarian cancer series . 
 however , real - time allele - specific pcr genotyping has detected only two brca1 4153dela carriers out of 177 unselected oc patients ( 1.1% ) . 
 both these carriers were early - onset and had serous carcinomas of grade 3 . 
 thus , our study supports neither the russian origin of brca1 4153dela mutation , nor its selectivity towards ovarian versus breast cancer predisposition .