Liquid Biopsy Revealed HBOC Pedigree and Led to Medical Management Among the Relatives

Aug 26, 2026

Hereditary breast and ovarian cancer (HBOC) was identified through liquid biopsy when BRCA genetic testing provided a definitive result. A 48-year-old woman with ovarian cancer received precision medicine using cell-free DNA from plasma, revealing a pathogenic BRCA1 variant consistent with a presumed germline pathogenic mutation. Germline confirmation of BRCA1 c.81-1G>A supported consideration of PARP inhibitor therapy, and testing in the family enabled surveillance recommendations for an unaffected pathogenic variant carrier child.

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CategoryHealthcare

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Case Report

Liquid biopsy and BRCA1 germline confirmation

Precision medicine and family management

Acta Med. Okayama, 2022 Vol. 76, No. 4, pp. 479-483 CopyrightⒸ2022 by Okayama University Medical School. Case Report [http:](http://escholarship.lib.okayama-u.ac.jp/amo/)[//](http://escholarship.lib.okayama-u.ac.jp/amo/)[escholarship.lib.okayama](http://escholarship.lib.okayama-u.ac.jp/amo/)[-](http://escholarship.lib.okayama-u.ac.jp/amo/)[u.ac.jp](http://escholarship.lib.okayama-u.ac.jp/amo/)[/](http://escholarship.lib.okayama-u.ac.jp/amo/)[amo](http://escholarship.lib.okayama-u.ac.jp/amo/)[/](http://escholarship.lib.okayama-u.ac.jp/amo/) Liquid Biopsy Revealed HBOC Pedigree and Led to Medical Management Among the Relatives Chikako Ogawaa＊, Akira Hirasawab, Reimi Sogawac, Kayoko Hasuokad, Shuta Tomidae, Mashu Futagawac, Yusaku Urakawab, Mariko Kochic, Hideki Yamamotob, Keiichiro Nakamuraa, and Hisashi Masuyamaa Departments of aObstetrics and Gynecology, bClinical Genomic Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Departments of cClinical Genetics and Genomic Medicine, dNursing, eCenter for Comprehensive Genomic Medicine, eOkayama University Hospital Biobank, Okayama University Hospital, Okayama 700-8558, Japan A hereditary breast and ovarian cancer (HBOC) pedigree was detected via liquid biopsy, and cancer prevention was initiated for the patient’s daughter, after receiving a definitive result from BRCA genetic testing. A 48-yearold woman with ovarian cancer was administered precision medicine, which used cell-free DNA from plasma. The results revealed a pathogenic variant of BRCA1 as a presumed germline pathogenic mutation. We confirmed the germline pathological variant BRCA1 c.81-1G> A and suggested treatment with a PARP inhibitor. One of her three children had the variant, was diagnosed as an unaffected pathogenic variant carrier, and was advised to initiate surveillance. Keywords: hereditary breast and ovarian cancer (HBOC), BRCA 1, presumed germline pathogenic variants (PGPV), germline findings, cancer precision medicine H e(reditarHBOCy), bretheastleanadidngovariacausenocfancerheredisyndrtary oovmareian cancer, is an autosomal dominant inherited cancer susceptibility disorder caused by pathogenic germline variants in BRCA1 or BRCA2 (BRCA1/2) . Ovarian, fallopian tube, and peritoneal carcinoma (OC) is the eighth most common cancer in women, and the eighth most common cause of cancer death worldwide, with over 313,900 new cases and 207,200 deaths reported annually [1 , 2] . Despite its low incidence, OC is the deadliest gynecological malignancy. In Japan, the age-adjusted mortality rate of ovarian cancer showed a strong increasing trend until the 1990s, and has remained high since then [3] . Although there are sev- Received November 19, 2021; accepted March 14, 2022. *Corresponding author. Phone : +81-86-235-7320; Fax : +81-86-225-9570 [E-mail : c.fukushima@cc.okayama-u.ac.jp](E-mail : c.fukushima@cc.okayama-u.ac.jp) (C. Ogawa) eral causes of OC, some hereditary tumor syndromes increase the incidence of OC [4 , 5] . Therefore, reduction in ovarian cancer deaths is important for BRCA1/2 pathogenic variant carriers. Although most cases of OC are sporadic, at least 10% of patients with OC have a genetic predisposition [6 , 7]. The frequency of pathogenic germline variants of cancer-related genes, including BRCA1/2, using multigene panel testing among Japanese ovarian cancer patients, was first reported by Hirasawa et al. [8] . A recent large-scale multi-cancer study reported that the overall prevalence of germline BRCA1/2 variants was 14.7% in Japanese patients with ovarian cancer [9] . The identification of these genes may provide benefits to individuals with a predisposition to OC with respect to Conflict of Interest Disclosures: No potential conflict of interest relevant to this article was reported. effective prevention strategies, including risk-reductive surgery, early diagnosis, and prediction of therapeutic efficacy, such as for pol

FAQs

How was the HBOC pedigree identified in the report?

The HBOC pedigree was detected via liquid biopsy using cell-free DNA from plasma after BRCA genetic testing provided a definitive result.

What BRCA-related finding was confirmed in the patient?

A pathogenic BRCA1 variant consistent with a presumed germline pathogenic mutation was identified, and the germline variant BRCA1 c.81-1G>A was confirmed.

How did the genetic results affect treatment and relatives?

The findings supported suggesting PARP inhibitor treatment and prompted testing and surveillance advice for an unaffected pathogenic variant carrier among the patient’s children.

Aug 26, 2026

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