Case series of Li-Fraumeni syndrome: carcinogenic mechanisms in breast cancer with TP53 pathogenic variant carriers.

BACKGROUND: Li-Fraumeni syndrome (LFS), a hereditary condition attributed to TP53 pathogenic variants,(PV), is associated with high risks for various malignant tumors, including breast cancer. Notably, individuals harboring TP53 PVs are more likely (67-83%) to develop HER2 + breast cancer than noncarriers (16-25%). In this retrospective study, we evaluated the associations between TP53 variants and breast cancer phenotype. METHODS: We conducted a retrospective review of the medical records of patients with LFS treated at a single institution and reviewed the literature on TP53 functions and the mechanisms underlying HER2 + breast cancer development in LFS. RESULTS: We analyzed data for 10 patients with LFS from 8 families. The median age at the onset of the first tumor was 35.5 years. Only case 2 met the classic criteria; this patient harbored a nonsense variant, whereas the other patients carried missense variants. We observed that 9 of 10 patients developed breast cancer. Immunohistochemical analyses revealed that 40% of breast cancers in patients with LFS were HR - /HER2 + . The median age at the onset of breast cancer was slightly younger in HR - /HER2 + tumors than in HR + /HER2 - tumors (31 years and 35.5 years, respectively). CONCLUSIONS: The occurrence of HER2 + breast cancer subtype was 40% in our LFS case series, which is greater than that in the general population (16-25%). Some TP53 PVs may facilitate HER2-derived oncogenesis in breast cancer. However, further studies with larger sample sizes are warranted to clarify the oncogenic mechanisms underlying each subtype of breast cancer in TP53 PV carriers.

High-risk pathogenic germline variants in blood relatives of BRCA1/2 negative probands.

BACKGROUND: Tailored, preventive cancer care requires the identification of pathogenic germline variants (PGVs) among potentially at-risk blood relatives (BRs). Cascade testing is carried out for BRs of probands who are positive for PGVs of an inherited cancer but not for negative probands. This study was conducted to examine the prevalence of PGVs for BRs of PGV-negative probands. METHODS: PGV prevalence was assessed for 682 BRs of 281 probands with BRCA1/BRCA2 wild-type hereditary breast and ovarian cancer (HBOC) syndrome. RESULTS: PGVs were discovered in 22 (45.8%) of the 48 BRs of the PGV-positive probands and in 14 (2.2%) of 634 BRs of the PGV-negative probands. Eleven PGVs on high-risk BRCA1, BRCA2, and TP53 genes were present only in BRs and not in the probands (probands vs BRs in Fisher exact test; p = 0.0104; odds ratio [OR] = 0.000 [0.000-0.5489 of 95% confidence interval]), partly due to the nature of the selection criteria. The enrichment of high-risk PGVs among BRs was also significant as compared with a non-cancer East Asian population (p = 0.0016; OR = 3.0791 [1.5521-5.6694]). PGV prevalence, risk class of gene, and genotype concordance were unaffected by the cancer history among BRs. CONCLUSION: These findings imply the necessity to construct a novel testing scheme to complement cascade testing.

Availability of genome-matched therapy based on clinical practice.

BACKGROUND: Comprehensive genomic profiling (CGP) provides new opportunities for patients with advanced cancer to receive genome-matched therapies, but the availability rate of these remains low. We reviewed our CGP cases and suggested possible strategies to improve the current status from a clinical perspective. METHODS: Druggable genomic alterations and barriers to accessing genome-matched therapies were investigated in 653 patients with 30 various types of cancers who underwent CGP. RESULTS: While the availability rate of genome-matched therapies as a whole was 9.5%, CGP was useful in some cancer types. Patients with thyroid cancer and lung cancer harbored druggable genomic alterations at high rates, while sarcoma rarely harbored these alterations (100%, 76%, and 15.2%, respectively). In contrast, the availability rate of genome-matched therapies was highest in patients with sarcoma and head and neck cancer (HNC) (60% and 40%, respectively). One hundred thirteen patients (63.5%) had multiple barriers to accessing genome-matched therapy. Of 178 patients, 21 patients (11.8%) could not be considered for genome-matched therapies solely because of the deterioration of their performance status. CONCLUSION: This study demonstrated the usefulness of CGP for patients with sarcoma and HNC in addition to lung cancer in clinical practice. Performing CGP at the front line has the potential to improve the availability of genome-matched therapy.

Risk of metachronous colorectal cancer after surgical resection of index rectal cancer in Lynch syndrome: a multicenter retrospective study in Japan.

PURPOSE: This study evaluated the risk of metachronous colorectal cancer (CRC) after resection of index (first) rectal cancer in patients with Lynch syndrome (LS). METHODS: Clinicopathological data of patients with genetically proven LS were retrospectively analyzed in this multicenter Japanese study. The cumulative incidence of metachronous CRC and the overall survival were compared between patients with index rectal cancer (rectal group) and those with index colon cancer (colon group). RESULTS: The median age at index CRC surgery was lower in the rectal group than in the colon group (37 vs. 46 years old, P = 0.01). The cumulative 5-, 10-, and 20-year incidences of metachronous CRC were 3.5%, 13.9%, and 21.1%, respectively, in the rectal cancer group and 14.9%, 22.0%, and 57.9%, respectively, in the colon cancer group (P = 0.02). The overall survival curves were not significantly different between two groups (P = 0.23). CONCLUSION: This is the first report from an East Asian country to report the risk of metachronous CRC after resection of index rectal cancer in patients with LS. Despite this study having several limitations, we cannot recommend extended resection, such as total proctocolectomy, for index rectal cancer as a standard surgical treatment in patients with LS.

Current prospects of hereditary adrenal tumors: towards better clinical management.

Adrenocortical carcinoma (ACC) and pheochromocytoma/paraganglioma (PPGL) are two rare types of adrenal gland malignancies. Regarding hereditary tumors, some patients with ACC are associated with with Li-Fraumeni syndrome (LFS), and those with PPGL with multiple endocrine neoplasia type 2. Recent studies have expanded this spectrum to include other types of hereditary tumors, such as Lynch syndrome or familial adenomatous polyposis. Individuals harboring germline TP53 pathogenic variants that cause LFS have heterogeneous phenotypes depending on the respective variant type. As an example, R337H variant found in Brazilian is known as low penetrant. While 50-80% of pediatric ACC patients harbored a LFS, such a strong causal relationship is not observed in adult patients, which suggests different pathophysiologies between the two populations. As for PPGL, because multiple driver genes, such as succinate dehydrogenase (SDH)-related genes, RET, NF1, and VHL have been identified, universal multi-gene germline panel testing is warranted as a comprehensive and cost-effective approach. PPGL pathogenesis is divided into three molecular pathways (pseudohypoxia, Wnt signaling, and kinase signaling), and this classification is expected to result in personalized medicine based on genomic profiles. It remains unknown whether clinical characteristics differ between cases derived from genetic predisposition syndromes and sporadic cases, or whether the surveillance strategy should be changed depending on the genetic background or whether it should be uniform. Close cooperation among medical genomics experts, endocrinologists, oncologists, and early investigators is indispensable for improving the clinical management for multifaceted ACC and PPGL.

Ovarian surveillance including endometrial cytology for patients with hereditary breast and ovarian cancer before risk-reducing salpingo-oophorectomy: A retrospective analysis.

AIM: Ovarian surveillance in women with hereditary breast and ovarian cancer who do not undergo risk-reducing salpingo-oophorectomy has been controversial. Therefore, this study aimed to demonstrate the clinical features of ovarian surveillance at our institution using a technique that combines serum cancer antigen 125 measurements, transvaginal ultrasonography, and uterine endometrial cytology. METHODS: We retrospectively examined 65 women, who had not undergone risk-reducing salpingo-oophorectomy diagnosed with hereditary breast and ovarian cancer between 2000 and 2021 at our hospital. Clinical information was obtained and analyzed through a chart review. The details of the treatment course were reviewed for patients who had developed ovarian cancer. RESULTS: Overall, 5 of the 65 women were diagnosed with ovarian cancer based on abnormal findings during periodic surveillance. All patients who developed ovarian cancer were asymptomatic, even if the cancer was at an advanced stage. Two of the 65 patients had endometrial cytology abnormalities, both of whom had ovarian cancer. All patients who developed ovarian cancer underwent primary debulking surgery, and complete gross resection was achieved. None of the patients experienced ovarian cancer recurrence. CONCLUSIONS: The ovarian surveillance strategy at our institution for women with hereditary breast and ovarian cancer who do not undergo risk-reducing salpingo-oophorectomy can identify asymptomatic ovarian cancer and contribute to achieving complete gross resection during primary surgery. Ovarian surveillance may contribute to a reduction in ovarian cancer mortality.

Risk-reducing decisions regarding germline BRCA pathogenic variant: focusing on the timing of genetic testing and RRSO.

BACKGROUND: In Japan, the public insurance policy was revised in 2020 to cover hereditary breast and ovarian cancer (HBOC), including genetic testing and surveillance, for patients with breast cancer (BC). Consequently, the demand for risk-reducing salpingo-oophorectomy (RRSO) has increased. This study aimed to clarify the changes in the demand and timing of genetic testing and RRSO associated with public insurance coverage for HBOC in Japan. METHODS: This retrospective analysis included 350 women with germline BRCA (gBRCA) pathogenic variants (PVs) who had visited gynaecologists; they received gBRCA genetic testing at 45.1±10.6 (20-74) years. The use of medical testing and preventive treatment was compared between the preinsurance and postinsurance groups using Mann-Whitney U and Fisher's exact tests. RESULTS: The findings indicate that RRSO rates doubled from 31.4% to 62.6% among patients with gBRCA-PV. The implementation rate was 32.4% among unaffected carriers and 70.3% among BC-affected patients. Younger patients received genetic testing with significantly shorter intervals between BC diagnosis and genetic testing and between genetic testing and RRSO. CONCLUSION: Overall, the insurance coverage for HBOC patients with BC has increased the frequency of RRSO in Japan. However, a comparison between the number of probands and family members indicated that the diagnosis among family members is inadequate. The inequality in the use of genetic services by socioeconomic groups is an issue of further concern.