Five screening-detected breast cancer cases in initially disease-free BRCA1 or BRCA2 mutation carriers.

Individuals carrying pathogenic BRCA1 or BRCA2 mutations have an increased lifetime risk of breast and/or ovarian cancer. The incidence of breast cancer amongst disease-free BRCA mutation carriers under surveillance and the clinical and pathological characteristics of those who subsequently develop the disease remain unclear in Japan. We reviewed the records of 155 individuals with BRCA1 or BRCA2 mutations identified by genetic testing between January 2000 and December 2016. At the time of genetic testing, 26 individuals with one of these mutations had no history of breast cancer and were therefore enrolled in a surveillance program that included biannual ultrasonography, clinical breast examination, annual mammography, and conditional magnetic resonance imaging for the early detection of primary breast cancer. During the surveillance period, 5 individuals with BRCA1 or BRCA2 mutations were diagnosed with primary breast cancer. The mean surveillance duration until breast cancer diagnosis was 48 months. The incidence of primary breast cancer during surveillance in initially disease-free BRCA mutation carriers was 4.23%/year. In two cases, the tumors were only detectable on MRI. The case 5 patient who presented with a tumor that was detected by self-examination, which then grew rapidly, had stage IIB triple-negative breast cancer. In conclusion, our results show that some challenges exist in the early detection of breast cancers in BRCA1 or BRCA2 mutation carriers. There are also some difficulties in approaching those individuals in Japanese society.

Mutation status of RAD51C, PALB2 and BRIP1 in 100 Japanese familial breast cancer cases without BRCA1 and BRCA2 mutations.

In addition to BRCA1 and BRCA2, RAD51C, PALB2 and BRIP1 are known as breast cancer susceptibility genes. However, the mutation status of these genes in Japanese familial breast cancer cases has not yet been evaluated. To this end, we analyzed the exon sequence and genomic rearrangement of RAD51C, PALB2 and BRIP1 in 100 Japanese patients diagnosed with familial breast and ovarian cancer and without BRCA1 and BRCA2 mutations. We detected a large deletion from exons 6 to 9 in RAD51C, 4 novel BRIP1 missense variants containing 3 novel non-synonymous variants, c.89A>C, c.736A>G and c.2131A>G, and a splice donor site variant c.918+2T>C. No deleterious variant of PALB2 was detected. The results of pedigree analysis showed that the proband with a large deletion on RAD51C had a family history of both breast and ovarian cancer, and the families of probands with novel BRIP1 missense variants included a male patient with breast cancer or many patients with breast cancer within the second-degree relatives. We showed that the mutation frequency of RAD51C in Japanese familial breast cancer cases was similar to that in Western countries and that the prevalence of deleterious mutation of PALB2 was possibly lower. Furthermore, our results suggested that BRIP1 mutation frequency in Japan might differ from that in Western countries.

Mutation analysis of MUTYH in Japanese colorectal adenomatous polyposis patients.

Germline MUTYH mutations were investigated in 14 Japanese colorectal polyposis patients without germ line adenomatous polyposis coli (APC) gene mutations. Three patients had a heterozygous IVS10-2A>G MUTYH mutation. The onset of MUTYH-associated polyposis (MAP) occurs later than that of familial adenomatous polyposis with germline APC mutation. Thus, we compared the carrier frequency of MUTYH IVS10-2A>G heterozygote in the APC mutation negative cases with that in 115 controls over 70 years of age who showed no apparent clinical manifestations of cancer and claimed that they had no history of cancer at the time of enrollment. The frequency of IVS10-2A>G heterozygote in APC germline mutation negative polyposis patients was significantly higher than control subject (p = 0.012, Chi square test). Although the sample size is still too small to conclude, the IVS10-2A>G MUTYH heterozygote might add to the risk of developing germline APC mutation negative polyposis.

Study on the psychosocial aspects of risk-reducing salpingo-oophorectomy (RRSO) in BRCA1/2 mutation carriers in Japan: a preliminary report.

OBJECTIVE: This study investigated the psychosocial aspects of risk-reducing salpingo-oophorectomy in Japan. METHODS: The subjects were 16 patients who underwent risk-reducing salpingo-oophorectomy at the Cancer Institute Hospital. Worry about cancer, emotional state and cancer-specific distress level were evaluated using a four-point Likert scale, the Profile of Mood States-Short Form and the Impact of Event Scale-Revised, respectively, before and 1 year after the surgery. In addition, the subjects were interviewed regarding their expectation for the risk-reducing surgery, the effects of the surgery, and the recovery from surgery, before the surgery and at 1, 6 and 12 months after the surgery. A t-test or Wilcoxon rank-sum test was used for the analysis, and literal analects were prepared for the interview and the answers were organized per question item using NVIVO10. RESULTS: The results revealed that the total score for worry about breast cancer and ovarian cancer (P = 0.021) as well as the Impact of Event Scale-Revised (P = 0.021) were significantly lower 1 year after surgery, compared with the values before the surgery. Regarding the preoperative expectations for the surgery, the expectation for reducing the cancer risk was the highest. The reported effects of risk-reducing salpingo-oophorectomy on life included the appearance of menopausal symptoms, a loss of motivation and poor concentration; more effects were reported at 1 year after surgery than at 6 months after surgery. CONCLUSIONS: These results suggest that risk-reducing salpingo-oophorectomy can be effective for reducing worry about breast cancer and ovarian cancer and cancer-specific distress as well as contributing to a reduction in mortality from fallopian tube and ovarian related cancer.

A case of early onset rectal cancer of Lynch syndrome with a novel deleterious PMS2 mutation.

Heterozygous deleterious mutation of the PMS2 gene is a cause of Lynch syndrome, an autosomal dominant cancer disease. However, the frequency of PMS2 mutation is rare compared with that of the other causative genes; MSH2, MLH1 and MSH6. PMS2 mutation has so far only been reported once from a Japanese facility. Detection of PMS2 mutation is relatively complicated due to the existence of 15 highly homologous pseudogenes, and its gene conversion event with the pseudogene PMS2CL. Therefore, for PMS2 mutation analysis, it is crucial to clearly distinguish PMS2 from its pseudogenes. We report here a novel deleterious 11 bp deletion mutation of exon 11 of PMS2 distinguished from PMS2CL in a 34-year-old Japanese female with rectal cancer. PMS2 mutated at c.1492del11 results in a truncated 500 amino acid protein rather than the wild-type protein of 862 amino acids. This is supported by the fact that, although there is usually concordance between MLH1 and PMS2 expression, cells were immunohistochemically positive for MLH1, whereas PMS2 could not be immunohistochemically stained using an anti-C-terminal PMS2 antibody, or effective PMS2 mRNA degradation with NMD caused by the frameshift mutation.

Identification of coding exon 3 duplication in the BMPR1A gene in a patient with juvenile polyposis syndrome.

Juvenile polyposis syndrome is an autosomal dominant inherited disorder characterized by multiple juvenile polyps arising in the gastrointestinal tract and an increased risk of gastrointestinal cancers, specifically colon cancer. BMPR1A and SMAD4 germline mutations have been found in patients with juvenile polyposis syndrome. We identified a BMPR1A mutation, which involves a duplication of coding exon 3 (c.230+452_333+441dup1995), on multiple ligation dependent probe amplification in a patient with juvenile polyposis syndrome. The mutation causes a frameshift, producing a truncated protein (p.D112NfsX2). Therefore, the mutation is believed to be pathogenic. We also identified a duplication breakpoint in which Alu sequences are located. These results suggest that the duplication event resulted from recombination between Alu sequences. To our knowledge, partial duplication in the BMPR1A gene has not been reported previously. This is the first case report to document coding exon 3 duplication in the BMPR1A gene in a patient with juvenile polyposis syndrome.

A case of a child with an APC pathogenic mutation, aberrant expression of splice variants and positive family history of FAP.

Familial adenomatous polyposis is an autosomal dominant hereditary disease characterized by the appearance of hundreds to thousands of colorectal adenomatous polyps; if left untreated, there is nearly a 100% lifetime risk of colorectal cancer. In the present case, adenomatous polyps were observed at 6 years of age. Unlike our previous assumption, adenomatous polyps were detected by colonoscopy at <10 years of age. Considering the clinical importance of early diagnosis, we report this case involving germline adenomatous polyposis coli mutation (c.1958G > C, GenBank: M74088.1) that caused an increase in the isoform without exon 15. Although this isoform has been reported previously, it remains controversial whether the variant is pathogenic or not because it was observed both in patients with familial adenomatous polyposis and in normal controls. Nonetheless, due to quantitative distortion of splice variants in adenomatous polyposis coli transcripts and the early development of adenomatous polyps, we believe that this variant may be pathogenic.