Incidence of contralateral and ipsilateral breast cancers and prognosis in BRCA1/2 pathogenic variant carriers based on the Japanese HBOC Consortium registration.

This study aimed to clarify the breast cancer prognosis in Japanese patients with BRCA1/2 pathogenic variant. We analyzed 2235 women with breast cancer who underwent BRCA1/2 genetic testing between 1996 and 2018 using data from the Japanese hereditary breast and ovarian cancer syndrome registry. The cumulative risk for contralateral and ipsilateral breast cancers and time to death since the first breast cancer were stratified based on the BRCA1/2 variant status. The median follow-up was 3.0 years (0.1-34.1 years) after the first breast cancer. The annual average risks of contralateral breast cancer in BRCA1 and BRCA2 and non-BRCA1/2 pathogenic variant carriers were 4.0%, 2.9%, and 1.9%, respectively (P = 0.001). The annual average risks of ipsilateral breast cancer in the three groups were 2.7%, 1.4%, and 1.1%, respectively (P = 0.06). BRCA1 pathogenic variant carriers had significantly higher risks of contralateral (hazard ratio 1.91, P < 0.001) and ipsilateral (hazard ratio 2.00, P = 0.02) breast cancers than non-BRCA1/2 pathogenic variant carriers. The time to death by the BRCA1/2 variant status was not significantly difference (P = 0.28). The prognosis of breast cancer patients who received standard treatment was comparable regardless of the BRCA1/2 variant status.

[Current Status and Prospects of the Comprehensive Cancer Genome Profiling].

In June 2019, 2 comprehensive cancer genome profiling(CGP)tests were approved with reimbursement, and are now available at designated hospitals stratified to 3 layers on the basis of their roles. The reimbursement-approved CGP tests were restricted to patients with solid tumors that have progressed on standard chemotherapy, rare tumors, or tumors of unknown primary, and perform primary structure analysis of cancer genome on several hundred genes at a time using next generation sequencer. In tumor molecular board, appropriate treatments were recommended based on the interpretation made for results of CGP. Because 2 CGP tests differ functionally in terms of the sample requirements, the target gene sets, and items to be reported, results need to be evaluated carefully. Although the detection rate of genomic alterations in CGP tests is high, the number of cases lead to treatments consistent with genomic alterations is limited. Improving this ratio will be the key for Japanese precision oncology to meet the full potential of the CGP tests.

[Current Status and Challenges of Clinical Practice for Hereditary Tumor Syndromes].

Somatic multiple-gene panel tests for cancer genome medicine and companion diagnostics, which diagnose or screen hereditary tumor syndromes along with selecting patients suitable for specific anticancer drugs, have been introduced to the clinical setting. Germline multi-gene panel tests also have begun to be used. In this situation, the traditional flow of the medical treatment for hereditary tumor syndromes is rapidly changing in Japan. It is anticipated that cases whose complicated germline genetic information is detected through approaches different from the traditional genetic testing flow will increase. It is necessary to develop systems that can lead to preventive intervention and treatment of cancer patients and previvors in his/her relatives through interpretation and communication of genetic information. In future medical treatment for hereditary tumor syndrome, flexible responses for various issues in a manner free from traditional are required not to be confined to the frame of conventional medical genetics.

A PDE3A mutation in familial hypertension and brachydactyly syndrome.

Hypertension and brachydactyly syndrome (HTNB) with short stature is an autosomal-dominant disorder. Mutations in the PDE3A gene located at 12p12.2-p11.2 were recently identified in HTNB families. We found a novel heterozygous missense mutation c.1336T>C in exon 4 of the PDE3A gene in a Japanese family with multiple HTNB patients. This mutation was found to be completely linked to the family members who inherited this condition. The mutation, resulting in p.Ser446Pro, was located within the cluster region of reported mutations. This mutation may also affect the phosphodiesterase activity of PDE3A to reduce the cyclic AMP level in the cell and thereby influencing the development of limbs and the function of the cardiovascular system.

Novel MLH1 nonsense variant in a patient with suspected Lynch syndrome.

Loss-of-function germline variants of MLH1 cause Lynch syndrome. Here, we present the case of a 43-year-old male patient diagnosed with cecal and transverse colon adenocarcinomas. The characteristics of the case met the revised Bethesda guidelines, and the tumors demonstrated a high frequency of microsatellite instability. Genetic testing for mismatch repair genes (indicative of Lynch syndrome) revealed a novel heterozygous germline pathogenic variant, NM_000249.4:c.856A>T/NP_000240.1:p.(Lys286Ter), in MLH1.

BARD1 deletion in a patient with suspected hereditary colorectal cancer.

Deleterious germline variants in the BRCA1-associated ring domain (BARD1) gene moderately elevate breast cancer risk; however, their potential association with other neoplasms remains unclear. Here, we present the case of a 43-year-old female patient diagnosed with sigmoid colon adenocarcinoma whose maternal family members met the Amsterdam Criteria II for Lynch syndrome. Comprehensive multigene panel testing revealed a heterozygous BARD1 exon 3 deletion.

Feasibility study of contralateral risk-reducing mastectomy with breast reconstruction for breast cancer patients with BRCA mutations in Japan.

BACKGROUND: Contralateral risk-reducing mastectomy (CRRM) for breast cancer patients with BRCA mutations has been reported to not only reduce breast cancer incidence but also to improve survival. The National Comprehensive Cancer Network guidelines recommend providing CRRM to women with BRCA mutations who desire CRRM after risk-reduction counseling. However, in Japan, CRRM cannot be performed generally because it is not covered by health insurance. Thus, we conducted a feasibility study to confirm the safety of CRRM. METHODS: CRRM with bilateral breast reconstructions were performed for breast cancer patients with BRCA mutations. The primary endpoint was early adverse events within 3 months, and secondary endpoints were late adverse events. RESULTS: Between August 2014 and November 2016, ten patients were enrolled. The median age was 37.5 years, and five of the patients had the BRCA1 mutation while five had the BRCA2 mutation. Six patients received neoadjuvant chemotherapy. Eight patients selected silicone breast implants, and two patients selected transverse rectus abdominis myocutaneous flap reconstruction. Pathological findings showed no evidence of occult breast cancers in any of the patients. At a median of 25.5 months follow-up time, CRRM-related early adverse events were hematoma (subsequently removed by re-operation; grade 2, n = 1), wound infection (grade 2, n = 1), skin ulceration (grade 1, n = 2) and wound pain (grade 1, n = 1). Overall, there were no grade 3 or more severe adverse events. CONCLUSION: Our results confirm that CRRM with reconstruction could be performed safely.