Precision medicine for hereditary tumors in gynecologic malignancies

Congenital and gynaecological tumors: A review

Congenital tumors are rare, and malignant congenital tumors are uncommon. Benign tu,mors might be life-threatening, depending on the location and size of the tumor. Different factors affect congenital tumors, such as maternal and placental hormones and environmental factors such as drugs, radiation, and infection. Developing fetal imaging methods and continuous follow-up during pregnancy are important factors in congenital tumor prognosis. Ultrasound is the most common method used for fetal evaluation. The complementary evaluation method is MRI. Both methods are helpful and widely spread for the detection of congenital tumors. These imaging methods help the medical team make a suitable decision about therapy. Some of these tumors regressed spontaneously, and some need surgical treatments. Treatment of tumors has developed rapidly, and recently molecular-targeted drugs have been used.

Meiotic protein SYCP2 confers resistance to DNA-damaging agents through R-loop-mediated DNA repair

Drugs targeting the DNA damage response (DDR) are widely used in cancer therapy, but resistance to these drugs remains a major clinical challenge. Here, we show that SYCP2, a meiotic protein in the synaptonemal complex, is aberrantly and commonly expressed in breast and ovarian cancers and associated with broad resistance to DDR drugs. Mechanistically, SYCP2 enhances the repair of DNA double-strand breaks (DSBs) through transcription-coupled homologous recombination (TC-HR). SYCP2 promotes R-loop formation at DSBs and facilitates RAD51 recruitment independently of BRCA1. SYCP2 loss impairs RAD51 localization, reduces TC-HR, and renders tumors sensitive to PARP and topoisomerase I (TOP1) inhibitors. Furthermore, our studies of two clinical cohorts find that SYCP2 overexpression correlates with breast cancer resistance to antibody-conjugated TOP1 inhibitor and ovarian cancer resistance to platinum treatment. Collectively, our data suggest that SYCP2 confers cancer cell resistance to DNA-damaging agents by stimulating R-loop-mediated DSB repair, offering opportunities to improve DDR therapy.

Simultaneous bilateral mastectomy and RRSO for BRCA2-positive non-invasive breast cancer in Japan: a case report and analysis of initial experience

BACKGROUND

In Japan, genetic testing, surveillance, and risk-reducing surgery for hereditary breast and ovarian cancer (HBOC) syndrome have been covered by the Japanese national insurance system since April 2020. On the other hand, the current situation is that medical care, including surveillance of undiagnosed (cancer-free) patients, is self-funded even for individuals with HBOC. We report a case in which breast cancer was diagnosed at an early stage during surveillance for cancer-free HBOC at the patient's own expense, and risk-reducing surgery was performed at the same time as treatment for breast cancer.

CASE PRESENTATION

The patient was a 63-year-old woman. Her sister had a history of breast cancer in her 30s and was found to be a BRCA2 pathogenic variant carrier by genetic testing. The patient therefore presented to the genetic department of our hospital and underwent genetic testing (out-of-pocket). A pathogenic variant was found at the same site. During annual breast and ovarian surveillance at the patient's own expense, a physician with sufficient expertise in contrast-enhanced breast magnetic resonance imaging (MRI) noticed a change in the contrast enhancement pattern on breast MRI and performed needle biopsy, revealing ductal carcinoma in situ. At the request of the patient, she underwent concurrent contralateral risk-reducing mastectomy and risk-reducing salpingo-oophorectomy in addition to breast cancer treatment.

CONCLUSIONS

We encountered a case in which cancer treatment and risk-reducing surgery were performed at the same time for a pathogenic variant carrier who was very anxious about developing cancer. Surveillance of cancer-free BRCA1/2 mutation carriers and expansion of insurance coverage for surgery are important future issues.

A Pathogenic Variant Reclassified to the Pseudogene PMS2P1 in a Patient with Suspected Hereditary Cancer

The PMS2 gene is involved in DNA repair by the mismatch repair pathway. Deficiencies in this mechanism have been associated with Lynch Syndrome (LS), which is characterized by a high risk for colorectal, endometrial, ovarian, breast, and other cancers. Germinal pathogenic variants of PMS2 are associated with up to 5% of all cases of LS. The prevalence is overestimated for the existence of multiple homologous pseudogenes. We report the case of a 44-year-old woman diagnosed with breast cancer at 34 years without a relevant cancer family history. The presence of pathogenic variant NM_000535.7:c.1A > T, (p.Met1Leu) in PMS2 was determined by next-generation sequencing analysis with a panel of 322 cancer-associated genes and confirmed by capillary sequencing in the patient. The variant was determined in six family members (brothers, sisters, and a son) and seven non-cancerous unrelated individuals. Analysis of the amplified region showed high homology of PMS2 with five of its pseudogenes. We determined that the variant is associated with the PMS2P1 pseudogene following sequence alignment analysis. We propose considering the variant c.1A > T, (p.Met1Leu) in PMS2 for reclassification as not hereditary cancer-related, given the impact on the diagnosis and treatment of cancer patients and families carrying this variant.

BRCA testing on buccal swab to improve access to healthcare and cancer prevention: a performance evaluation

OBJECTIVE

BRCA1/2 (BRCA) genetic testing allows patients with high-grade serous ovarian cancer to receive appropriate medical management with molecular target therapy and prevention strategies. Most of the BRCA sequencing methods use blood as the primary source of germline DNA. Buccal swab emerged as an alternative collection device due to its convenient and non-invasive characteristics. This study assessed the suitability of buccal swabs as the DNA source in next-generation sequencing-based BRCA genotyping.

METHODS

Matched buccal swabs and blood samples were collected from 51 patients with high-grade serous ovarian cancer, including 29 BRCA-mutated patients, from June to December 2021. Buccal swabs were self-collected using COPAN FLOQSwabs hDNA Free. BRCA genes were amplified using Devyser's BRCA next-generation sequencing kit and sequenced on the Illumina MiSeq platform. We evaluated collection and extraction procedures, amplification and sequencing performances, coverage data, blood/swab variant calling concordance, and interpretation.

RESULTS

Comparable sequencing parameters were observed between the two sample types in term of mean total number of reads passing filter for indexed sample (p>0.05) and sequencing coverage distribution, with a widespread overlap of mean depth of coverage/target region between blood and swab samples. An overall concordance of 100% in both polymorphisms and pathogenic variants calling between the two DNA sources were observed, including the copy number variation prediction.

CONCLUSIONS

Data from this study support the use of buccal swabs as an alternative source of DNA for BRCA evaluation. The use of this alternative delivery mode of BRCA testing may facilitate access to care without compromising patient outcomes.

Correlation between the risk of ovarian cancer and BRCA recurrent pathogenic variants in Japan

We previously reported that L63X and Q934X are BRCA1 common founder variants in Japan. So far, there have been no reports of a correlation between such BRCA common variants and the risk of BRCA-related cancers. In this analysis, we investigated the correlation between the risk of ovarian cancer (OC) and BRCA recurrent pathogenic variants. We examined the database of the Japanese organization of hereditary breast and ovarian cancer. The database contained 3517 probands who underwent BRCA genetic testing. Among them, 11.1% (392/3517) had germline BRCA1 pathogenic variant, and 8.3% (293/3517) had BRCA2 pathogenic variant. We calculated the OC prevalence, breast cancer (BC) prevalence, and the ratio of OC to BC within second-degree relatives. The ratio of OC to BC in Q934X family members was significantly higher than that in the overall BRCA1 family members (0.80 vs.0.52: p = 0.038), and the ratio in STOP799 was 0.42, which was relatively lower than the overall BRCA1 value. Both Q934X and STOP799 are located in the ovarian cancer cluster region (OCCR), however there seems to be a difference in the risk of OC. R2318X family members had a significant higher ratio of OC to BC at 0.32 than the overall BRCA2 value of 0.13 (p = 0.012). R2318X is known to be located in the OCCR. This is the first report to investigate the correlation between BRCA recurrent variants and the risk of OC in Japan. The family members of probands with Q934X or R2318X have a higher risk of OC than that with other BRCA variants.

Differences in age at diagnosis of ovarian cancer for each BRCA mutation type in Japan: optimal timing to carry out risk-reducing salpingo-oophorectomy

Objective

BRCA1 and BRCA2 mutation carriers are recommended to undergo risk-reducing salpingo-oophorectomy (RRSO) by age 40 and 45, respectively. However, the carriers have a different way of thinking about their life plan. We aimed to investigate the distribution of age at diagnosis of ovarian cancer (OC) patients to examine the optimal timing of RRSO in the carriers.

Methods

We examined a correlation between age at diagnosis of OC and common mutation types in 3,517 probands that received BRCA genetic testing. Among them, germline BRCA1 mutation (gBRCA1m), germline BRCA2 mutation (gBRCA2m) and germline BRCA wild-type (gBRCAwt) were found in 185, 42 and 241 OC patients, respectively.

Results

The average age at diagnosis of OC in gBRCA1m and gBRCA2m was 51.3 and 58.3 years, respectively, and the difference from gBRCAwt (53.8 years) was significant. The gBRCA2m carriers did not develop OC under the age of 40. The average age was 50.1 years for L63X and 52.8 years for Q934X in BRCA1, and 55.1 years for R2318X and 61.1 years for STOP1861 in BRCA2. The age at diagnosis in L63X or R2318X carriers was relatively younger than other BRCA1 or BRCA2 carriers, however their differences were not significant. With L63X and R2318X carriers, 89.4% (42/47) and 100% (7/7) of women were able to prevent the development of OC, respectively, when RRSO was performed at age 40.

Conclusion

There appears to be no difference in the age at diagnosis of OC depending on the type of BRCA common mutation. Further analysis would be needed.

This is the first report to present the optimal timing of risk-reducing salpingo-oophorectomy for each BRCA mutation type in Japan. The average age at diagnosis of ovarian cancer (OC) in germline BRCA2 mutation (gBRCA2m) is higher than that in germline BRCA wild-type. The gBRCA2m carriers did not develop OC under the age of 40. The average age at diagnosis in L63X or R2318X carriers was relatively younger than other BRCA mutation carriers, though the differences were not significant.

Lynch Syndrome and MSI-H Cancers: From Mechanisms to "Off-The-Shelf" Cancer Vaccines

Defective DNA mismatch repair (dMMR) is associated with many cancer types including colon, gastric, endometrial, ovarian, hepatobiliary tract, urinary tract, brain and skin cancers. Lynch syndrome - a hereditary cause of dMMR - confers increased lifetime risk of malignancy in different organs and tissues. These Lynch syndrome pathogenic alleles are widely present in humans at a 1:320 population frequency of a single allele and associated with an up to 80% risk of developing microsatellite unstable cancer (microsatellite instability - high, or MSI-H). Advanced MSI-H tumors can be effectively treated with checkpoint inhibitors (CPI), however, that has led to response rates of only 30-60% despite their high tumor mutational burden and favorable immune gene signatures in the tumor microenvironment (TME). We and others have characterized a subset of MSI-H associated highly recurrent frameshift mutations that yield shared immunogenic neoantigens. These frameshifts might serve as targets for off-the-shelf cancer vaccine designs. In this review we discuss the current state of research around MSI-H cancer vaccine development, its application to MSI-H and Lynch syndrome cancer patients and the utility of MSI-H as a biomarker for CPI therapy. We also summarize the tumor intrinsic mechanisms underlying the high occurrence rates of certain frameshifts in MSI-H. Finally, we provide an overview of pivotal clinical trials investigating MSI-H as a biomarker for CPI therapy and MSI-H vaccines. Overall, this review aims to inform the development of novel research paradigms and therapeutics.

Differences in Ovarian and Other Cancers Risks by Population and BRCA Mutation Location

Hereditary breast and ovarian cancer is caused by a germline mutation in BRCA1 or BRCA2 genes. The frequency of germline BRCA1/2 gene mutation carriers and the ratio of germline BRCA1 to BRCA2 mutations in BRCA-related cancer patients vary depending on the population. Genotype and phenotype correlations have been reported in BRCA mutant families, however, the correlations are rarely used for individual risk assessment and management. BRCA genetic testing has become a companion diagnostic for PARP inhibitors, and the number of families with germline BRCA mutation identified is growing rapidly. Therefore, it is expected that analysis of the risk of developing cancer will be possible in a large number of BRCA mutant carriers, and there is a possibility that personal and precision medicine for the carriers with specific common founder mutations will be realized. In this review, we investigated the association of ovarian cancer risk and BRCA mutation location, and differences of other BRCA-related cancer risks by BRCA1/2 mutation, and furthermore, we discussed the difference in the prevalence of germline BRCA mutation in ovarian cancer patients. As a result, although there are various discussions, there appear to be differences in ovarian cancer risk by population and BRCA mutation location. If it becomes possible to estimate the risk of developing BRCA-related cancer for each BRCA mutation type, the age at risk-reducing salpingo-oophorectomy can be determined individually. The decision would bring great benefits to young women with germline BRCA mutations.