Background: A positive BRCA1/2 carrier status impacts an individual on various levels with implications to an entire family due to shared family genes. A gap exists in the research literature in the area of parental disclosure and non-disclosure of genetic test results to younger offspring. Additional studies in the area of parental disclosure and non-disclosure will help clinicians to better support parents and children during this process. Purpose: The purpose of this qualitative hermeneutic phenomenological research study was to attain an understanding of the lived experience of parents’ perceptions regarding the disclosure and non-disclosure of a positive BRCA1/2 test result to minors. Results: The essence of the lived experience of the 15 study participants was a parental desire for healthcare professionals to take the BRCA1/2 conversation a step further which was uncovered in the seven research themes. Discussion: For the study participants interviewed, stories reflected an identified need for axillary support that specifically pertained to the disclosure and non-disclosure decision-making process. Findings suggest ways in which parental support may be coordinated though intra and interdisciplinary team approaches to patient care. Implications: The findings from this study support the need for mixed methods studies of parental disclosure and non-disclosure of BRCA1/2 test results to minors. Specifically, studies assessing positive BRCA1/2 males and individuals from our gay community, members from our lower socioeconomic and diverse ethnic community, and fathers and children’s perceptions regarding the disclosure of parental BRCA1/2 test results to minors are warranted.

Det finns flera olika typer av en bröstcancergen, två av dessa cancergener är BRCA 1 och 2. Dessa cancergener är ärftliga och risken för att utveckla bröst eller livmodercancer blir upp till 80 % när man är bärare redan vid 30 års ålder. Syftet är att beskriva unga kvinnors upplevelser av att leva med genmutation BRCA 1 och/eller BRCA 2. Studien är en litteraturstudie. Dataanalysen mynnade ut i fyra teman känsla av hotad existens, behov av stöd för att hantera information, avsaknad av samhörighet och etiskt dilemma. Resultatet lyfter fram de upplevelser och fruktan som är central för unga kvinnor när de får besked om att vara bärare av BRCA 1 eller 2 och de beslut de måste ta som kan påverka livet och framtiden. Studiens resultat är användbart för vårdpersonal och närstående som möter dessa unga kvinnor och kan ge en större förståelse för känslor och upplevelser som uppstår som bärare på en cancergen.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23083号 / 医博第4710号 / 新制||医||1049(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 中島 貴子, 教授 近藤 玄, 教授 小杉 眞司 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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Purpose: This study assessed effectiveness of five tools recommended by the US Preventive Services Task Force (USPSTF), designed to help primary care clinicians determine which unaffected patients to refer to genetics specialists for breast cancer risk assessment based on concerning family history. Design: This descriptive secondary analysis included 85 women aged 40-74. All participants had a first-degree female relative previously diagnosed with breast cancer who also had uninformative negative BRCA1/2 tests. Methods: Each pedigree was evaluated using the five tools including the Family History Screen-7 (FHS-7), Pedigree Assessment Tool (PAT), Manchester Scoring System, Referral Screening Tool (RST), and Ontario-Family History Assessment Tool (Ontario-FHAT). All five tools were applied to each study participant. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated to describe each tool’s ability to identify women with elevated risk as calculated by the Claus model. Receiver operating curves (ROC) were also plotted. Differences between areas under the curve (AUCs) for all possible pairs of tools were estimated through logistic regression to assess for differences in tool performance. Results: Claus calculations identified 14 women out of 85 whose lifetime risk of breast cancer was elevated at > 15%. Only two tools, the Ontario-FHAT and FHS-7, identified all 14 women with elevated risk, a sensitivity of 100%. The FHS-7 tool flagged all 85 participants, meaning its specificity was zero. The Ontario-FHAT flagged 59 participants as needing referral (specificity 36.2%) and had a negative predictive value (NPV) of 100%, indicating that if a woman was not found to need a referral to a genetics professional, it is likely she did not have an elevated lifetime risk of developing breast cancer. AUC values were not significantly different between tools (all p values > .05), and thus were not helpful in discriminating between the tools. Conclusion: In this population, the Ontario-FHAT out-performed other tools in terms of sensitivity and negative predictive value; however, low specificity and positive predictive value must be balanced against these findings. Thus, the Ontario-FHAT can help determine which women would benefit from referral to a genetics specialist.

Genetic test results have important implications for close family members. Indeterminate negative results are the most common outcome of BRCA1/2 mutation testing. Little is known about family members' understanding of indeterminate negative BRCA1/2 test results. The purpose of this qualitative descriptive study was to investigate how daughters and sisters received and understood genetic test results as shared by their mothers or sisters. Participants included 81 women aged 40-74 with mothers or sisters previously diagnosed with breast cancer and who received indeterminate negative BRCA1/2 test results. Participants had never been diagnosed with breast cancer nor received their own genetic testing or counseling. This IRB approved study utilized semi-structured interviews administered via telephone. The research team developed descriptive codes, and NVIVO software was used during qualitative analysis. Participants reported low amounts of information shared with them. Most women described test results as negative and incorrectly interpreted the test to mean there was no genetic component to the pattern of cancer in their families. Only 7 of 81 women accurately described test results consistent with the meaning of an indeterminate negative result — meaning a genetic cause for cancer in their family could still exist. Our findings demonstrate that indeterminate negative genetic test results are not well understood by family members. Lack of understanding may lead to an inability to effectively communicate results to primary care providers and missed opportunities for prevention, screening and further genetic testing. We recommend providing family members letters they can share with their own primary care providers whenever genetic testing is performed.

Mutations in the hereditary breast/ovarian cancer genes BRCA1/2 were shown to be synthetic lethal with poly(ADP-ribose) polymerase inhibitors (PARPi). This toxicity is assumed to derive from PARPi-induced DNA double strand breaks (DSBs) that necessitate BRCA function in homologous recombination (HR) and/or fork protection (FP). However, PARPi accelerates replication forks. While high-speed replication could cause DSBs, the finding that PARPi leads to single-stranded DNA (ssDNA) gaps/nicks suggests replication gaps could also or alone be the cause of synthetic lethality. Here, we demonstrate that PARPi toxicity derives from replication gaps. Isogenic cells deficient in BRCA1 or the BRCA1-associated FANCJ, with common DNA repair defects in HR and FP, exhibit opposite responses to PARPi. Deficiency in FANCJ, a helicase also mutated in hereditary breast/ovarian cancer and Fanconi anemia, causes aberrant accumulation of fork remodeling factor HLTF and limits unrestrained DNA synthesis with ssDNA gaps. Thus, we predict replication gaps as a distinguishing factor and further uncouple HR, FP and fork speed from PARPi response. BRCA-deficient cells display excessive gaps that are diminished upon resistance, restored upon re-sensitization and when targeted augment synthetic lethality with PARPi. Furthermore, we define the source of gaps to defects in Okazaki fragment processing (OFP). Unchallenged BRCA1-deficient cells have elevated poly(ADP-ribose) and chromatin-associated PARP1 but aberrantly low XRCC1 indicating a defective backup OFP pathway. Remarkably, 53BP1 loss resuscitates OFP by restoring XRCC1-LIG3 that suppresses the sensitivity of BRCA1-deficient cells to drugs targeting OFP or generating gaps. Collectively, our study highlights unprotected lagging strand gaps as a determinant of synthetic lethality, providing a new paradigm and biomarker for PARPi toxicity.