Enhancement of Haloperidol-Induced Catalepsy by GPR143, an L-Dopa Receptor, in Striatal Cholinergic Interneurons.

Dopamine neurons play crucial roles in pleasure, reward, memory, learning, and fine motor skills and their dysfunction is associated with various neuropsychiatric diseases. Dopamine receptors are the main target of treatment for neurologic and psychiatric disorders. Antipsychotics that antagonize the dopamine D2 receptor (DRD2) are used to alleviate the symptoms of these disorders but may also sometimes cause disabling side effects such as parkinsonism (catalepsy in rodents). Here we show that GPR143, a G-protein-coupled receptor for L-3,4-dihydroxyphenylalanine (L-DOPA), expressed in striatal cholinergic interneurons enhances the DRD2-mediated side effects of haloperidol, an antipsychotic agent. Haloperidol-induced catalepsy was attenuated in male Gpr143 gene-deficient (Gpr143-/y ) mice compared with wild-type (Wt) mice. Reducing the endogenous release of L-DOPA and preventing interactions between GPR143 and DRD2 suppressed the haloperidol-induced catalepsy in Wt mice but not Gpr143-/y mice. The phenotypic defect in Gpr143-/y mice was mimicked in cholinergic interneuron-specific Gpr143-/y (Chat-cre;Gpr143flox/y ) mice. Administration of haloperidol increased the phosphorylation of ribosomal protein S6 at Ser240/244 in the dorsolateral striatum of Wt mice but not Chat-cre;Gpr143flox/y mice. In Chinese hamster ovary cells stably expressing DRD2, co-expression of GPR143 increased cell surface expression level of DRD2, and L-DOPA application further enhanced the DRD2 surface expression. Shorter pauses in cholinergic interneuron firing activity were observed after intrastriatal stimulation in striatal slice preparations from Chat-cre;Gpr143flox/y mice compared with those from Wt mice. Together, these findings provide evidence that GPR143 regulates DRD2 function in cholinergic interneurons and may be involved in parkinsonism induced by antipsychotic drugs.

Development of a novel prediction model for carriage of BRCA1/2 pathogenic variant in Japanese patients with breast cancer based on Japanese organization of hereditary breast and ovarian cancer registry data.

PURPOSE: With the increasing demand for BRCA genetic testing, most existing prediction models were developed using data from individuals of European descent. This study aimed to identify clinicopathological factors of hereditary breast and ovarian cancer (HBOC) syndrome and develop the first Japanese-specific prediction model for BRCA pathogenic variant carriers in Japan. METHODS: We utilized data from 3072 Japanese patients with breast cancer aggregated by the Japanese Organization of Hereditary Breast and Ovarian Cancer registry. Prediction models were developed using 70% of the overall dataset and validated using the remaining 30%. Factors associated with the BRCA pathogenic variant status were identified using logistic univariate analysis, and significant factors were further analyzed using logistic multivariate analysis to develop prediction models for BRCA1/2 (BRCA1 and/or BRCA2), BRCA1, and BRCA2 pathogenic variants. RESULTS: BRCA1 showed associations with aggressive clinicopathological factors such as triple-negative breast cancer and nuclear grade 3. Moreover, the prediction model showed a high area under the curve (AUC) of 0.879. By contrast, BRCA2 exhibited fewer characteristic associated factors, and the AUC of the model was 0.669. Common factors shared by BRCA1/2, BRCA1, and BRCA2 were the age at diagnosis of breast cancer and the youngest age of relatives with breast cancer. Consistent with previous research, early-onset breast cancer appeared to be strongly associated with HBOC. CONCLUSION: We successfully developed prediction models for BRCA1/2, BRCA1, and BRCA2 pathogenic variants. By accurately stratifying patients' risk and guiding targeted screening and preventative interventions, these models will contribute to improved management and outcomes of HBOC.

BRCAness of brain lesions reflects a worse outcome for patients with metastatic breast cancer.

PURPOSE: Breast cancer often metastasizes to the central nervous system. Although the prognosis of brain metastases from breast cancer has been considered poor, and systemic therapy has not contributed to an improved prognosis, newer agents are expected to be more effective. BRCAness is defined as the status of homologous recombination deficiency (HRD) in tumor tissue, regardless of the presence of pathogenic germline BRCA1/2 variants. A study employing next-generation sequencing analysis showed that HRD was found relatively frequently in brain metastases of breast cancer patients. However, there have been no studies evaluating BRCAness in brain metastases of breast cancer with more efficient, rapid, and cost-effective methods. METHODS: We retrospectively investigated 17 brain metastases of breast cancer that were surgically resected at our hospital from January 2007 to December 2022. Of these, samples from 15 patients were evaluable for BRCAness by employing multiplex ligation-dependent probe amplification (MLPA) assay. RESULTS: Of the 15 patients, five patients (33%) had tumors with BRCAness. Clinicopathological factors of patients with brain metastases with BRCAness were not statistically different from those of patients who possessed tumors without BRCAness. Patients with brain metastases with BRCAness had shorter overall survival compared to those without BRCAness (BRCAness, median 15 months (95% CI 2-30) vs. non-BRCAness, median 28.5 months (95% CI 10-60); P = 0.013). CONCLUSION: In this study, we evaluated BRCAness in brain metastases of breast cancer with the MLPA method, and found that about one-third of patients had BRCAness-positive tumors. The analysis of BRCAness using MLPA has the potential for practical clinical use.

Opposite regulation by L-DOPA receptor GPR143 of the long and short forms of the dopamine D2 receptors.

Dopamine (DA) D2 receptors (D2Rs) have 2 isoforms, a long form (D2L) and a short form (D2S). D2L is predominantly postsynaptic in the striatal medium spiny neurons and cholinergic interneurons. D2S is principally presynaptic autoreceptors in the nigrostriatal DA neurons. Recently, we demonstrated that L-3,4-dihydroxyphenylalanine (L-DOPA) augments D2L function through the coupling between D2L and GPR143, a receptor of L-DOPA that was originally identified as the gene product of ocular albinism 1. Here we show that GPR143 modifies the functions of D2L and D2S in an opposite manner. Haloperidol-induced catalepsy was attenuated in DA neuron-specific Gpr143 gene-deficient (Dat-cre;Gpr143flox/y) mice, compared with wild-type (Wt) mice. Haloperidol increased in vivo DA release from the dorsolateral striatum, and this increase was augmented in Gpr143-/y mice compared with Wt mice. A D2R agonist quinpirole-induced increase in the phosphorylation of GSK3ß(pGSK3ß(S9)) was enhanced in Chinese hamster ovary (CHO) cells coexpressing D2L and GPR143 compared with cells expressing D2L alone, while it was suppressed in cells coexpressing D2S and GPR143 compared with D2S alone, suggesting that GPR143 differentially modifies D2R functions depending on its isoforms of D2L and D2S.

Symptoms and age of prodromal Alzheimer's disease in Down syndrome: a systematic review and meta-analysis.

The diagnostic criteria for adult-onset Alzheimer's disease (AD) in patients with Down syndrome (DS) have not been standardised. This study investigated the specific symptoms of AD in the prodromal stage of DS, the mean age at diagnosis at each stage of dementia, and the relationship between intellectual disability (ID) and dementia. PubMed, Web of Science, and Embase were searched for studies on DS, AD, early-stage disease, initial symptoms, and prodromal dementia registered between January 2012 and January 2022. We also performed a meta-analysis of the differences between the mean age at prodromal symptoms and AD diagnosis and the proportion of mild cognitive impairment in patients with mild and moderately abnormal ID. We selected 14 articles reporting the behavioural and psychological symptoms of dementia (BPSD) and memory- and language-related impairments as early symptoms of AD in patients with DS. The specific symptoms of BPSD were classified into five categories: irritability (agitation), apathy, abnormal behaviour, adaptive functioning, and sleep disturbance. The mean age at the diagnosis of prodromal symptoms and AD dementia was 52.7 and 56.2 years, respectively (mean difference, + 3.11 years; 95% CI 1.82-4.40) in the meta-analysis. The diagnosis of mild dementia tended to correlate with ID severity (odds ratio [OR], 1.38; 95% CI 0.87-2.18). The features of behaviour-variant frontotemporal dementia may be clinically confirmed in diagnosing early symptoms of DS-associated AD (DSAD). Moreover, age-appropriate cognitive assessment is important. Further studies are required to evaluate DSAD using a combination of biomarkers and ID-related data.

Coupling between GPR143 and dopamine D2 receptor is required for selective potentiation of dopamine D2 receptor function by L-3,4-dihydroxyphenylalanine in the dorsal striatum.

Dopamine (DA) is involved in neurological and physiological functions such as motor control. L-3,4-dihydroxyphenylalanine (L-DOPA), a precursor of DA, is conventionally believed to be an inert amino acid precursor of DA, and its major therapeutic effects in Parkinson's disease (PD) are mediated through its conversion to DA. On the contrary, accumulating evidence suggests that L-DOPA itself is a neurotransmitter. We here show that L-DOPA potentiates DA D2 receptor (DRD2) signaling through GPR143, the gene product of X-linked ocular albinism 1, a G-protein-coupled receptor for L-DOPA. In Gpr143-gene-deficient (Gpr143-/y ) mice, quinpirole, a DRD2/DRD3 agonist, -induced hypolocomotion was attenuated compared to wild-type (WT) mice. Administration of non-effective dose of L-DOPA methyl ester augmented the quinpirole-induced hypolocomotion in WT mice but not in Gpr143-/y mice. In cells co-expressing GPR143 and DRD2, L-DOPA enhanced the interaction between GPR143 and DRD2 and augmented quinpirole-induced decrease in cAMP levels. This augmentation by L-DOPA was not observed in cells co-expressing GPR143 and DRD1 or DRD3. Chimeric analysis in which the domain of GPR143 was replaced with GPR37 revealed that GPR143 interacted with DRD2 at the fifth transmembrane domain. Intracerebroventricular administration of a peptide that disrupted the interaction mitigated quinpirole-induced behavioral changes in WT mice but not in Gpr143-/y mice. These findings provide evidence that coupling between GPR143 and DRD2 is required for selective DRD2 modulation by L-DOPA in the dorsal striatum.

The pathogenic role of the BRCA2 c.7847C>T (p.Ser2616Phe) variant in breast and ovarian cancer predisposition.

Substantial numbers of variants of unknown significance (VUSs) have been identified in BRCA1/2 through genetic testing, which poses a significant clinical challenge because the contribution of these VUSs to cancer predisposition has not yet been determined. Here, we report 10 Japanese patients from seven families with breast or ovarian cancer harboring the BRCA2 c.7847C>T (p.Ser2616Phe) variant that was interpreted as a VUS. This variant recurs only in families from Japan and has not been reported in the global general population databases. A Japanese patient with Fanconi anemia with compound heterozygous variants c.7847C>T (p.Ser2616Phe) and c.475+1G>A in BRCA2 was reported. In silico predictions and quantitative cosegregation analysis suggest a high probability of pathogenicity. The clinical features of the variant carriers were not specific to, but were consistent with, those of patients with hereditary breast and ovarian cancer. A validated functional assay, called the mixed-all-nominated-in-one-BRCA (MANO-B) method and the accurate BRCA companion diagnostic (ABCD) test, demonstrated the deleterious effects of the variant. Altogether, following the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) guidelines, this variant satisfied the "PS3," "PM2," "PM3," and "PP3" criteria. We thus conclude that the BRCA2 c.7847C>T (p.Ser2616Phe) variant is a "likely pathogenic" variant that is specifically observed in the Japanese population, leading to a breast and ovarian cancer predisposition.

Functional evaluation of BRCA1/2 variants of unknown significance with homologous recombination assay and integrative in silico prediction model.

Numerous variants of unknown significance (VUSs) exist in hereditary breast and ovarian cancers. Although multiple methods have been developed to assess the significance of BRCA1/2 variants, functional discrepancies among these approaches remain. Therefore, a comprehensive functional evaluation system for these variants should be established. We performed conventional homologous recombination (HR) assays for 50 BRCA1 and 108 BRCA2 VUSs and complementarily predicted VUSs using a statistical logistic regression prediction model that integrated six in silico functional prediction tools. BRCA1/2 VUSs were classified according to the results of the integrative in vitro and in silico analyses. Using HR assays, we identified 10 BRCA1 and 4 BRCA2 VUSs as low-functional pathogenic variants. For in silico prediction, the statistical prediction model showed high accuracy for both BRCA1 and BRCA2 compared with each in silico prediction tool individually and predicted nine BRCA1 and seven BRCA2 variants to be pathogenic. Integrative functional evaluation in this study and the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) guidelines strongly suggested that seven BRCA1 variants (p.Glu272Gly, p.Lys1095Glu, p.Val1653Leu, p.Thr1681Pro, p.Phe1761Val, p.Thr1773Ile, and p.Gly1803Ser) and four BRCA2 variants (p.Trp31Gly, p.Ser2616Phe, p.Tyr2660Cys, and p.Leu2792Arg) were pathogenic. This study demonstrates that integrative evaluation using conventional HR assays and optimized in silico prediction comprehensively classified the significance of BRCA VUSs for future clinical applications.

Involvement of the L-DOPA receptor GPR143 in acute and chronic actions of methylphenidate.

Methylphenidate (MPH) and methamphetamine (METH) are the current treatments of choice for attention deficit/hyperactivity disorder. We previously reported that METH induces the release of dopamine (DA) and of the neurotransmitter candidate L-3,4-dihydroxyphenylalanine (L-DOPA). In contrast, we here found that MPH increased the DA release while it did not affect the L-DOPA release from the dorsolateral striatum. Nevertheless, MPH-induced hyperlocomotion was reduced in Gpr143 (L-DOPA receptor) gene-deficient (Gpr143-/y) mice. The rewarding effect and increased c-fos expression induced by MPH were also attenuated in Gpr143-/y mice. Together, these findings suggest that GPR143 is involved in the acute and chronic actions of MPH.

The prevalence of lynch syndrome (DNA mismatch repair protein deficiency) in patients with primary localized prostate cancer using immunohistochemistry screening.

BACKGROUND: Prostate cancer is one of the most heritable human cancers. Lynch syndrome is an autosomal dominant inheritance caused by germline mutations in DNA mismatch repair (MMR) genes, which are also associated with an increased incidence of prostate cancer. However, prostate cancer has not been defined as a Lynch syndrome-associated cancer. The proportion of Lynch syndrome patients in primary prostate cancers is unclear. In this study, we investigated MMR protein loss using universal immunohistochemical screening to determine the prevalence of Lynch syndrome in patients with localized prostate cancer who underwent radical prostatectomy. METHODS: One hundred twenty-nine surgical specimens from radical prostatectomy performed at Toranomon Hospital between 2012 and 2015 were retrospectively tested using universal screening with immunohistochemistry staining for expression of the MMR proteins MLH1, PMS2, MSH2, and MSH6. For all suspected MMR-deficient patients, germline genetic tests focusing on MMR genes were performed. RESULTS: MMR protein loss was found in only one patient (0.8%) who showed dual MSH2/MSH6 loss. This patient showed a single nucleotide pathogenic germline mutation from c.1129 C to T (p.Gln377*) at exon 7 in the MSH2 gene. He was diagnosed with a primary prostate cancer at 66 years of age. He had a documented history of Lynch syndrome (Muir-Torre syndrome) with previous colon cancer, sebaceous tumor, and keratoacanthoma as well as subsequent bladder cancer, all of which also showed dual MSH2/MSH6 loss. He also had a strong family history of colorectal and other Lynch syndrome-associated cancers. The pathological stage was pT3aN0M0, and the pathological grade was Gleason 7(4 + 3) with tertiary pattern 5. CONCLUSIONS: In this study, immunohistochemical screening of MMR proteins for Lynch syndrome was performed in a series of prostate cancer cases. The prevalence of Lynch syndrome in localized prostate cancer was 0.8%, which is low compared with other Lynch syndrome-associated cancers.

Brca1L63X /+ rat is a novel model of human BRCA1 deficiency displaying susceptibility to radiation-induced mammary cancer.

Women who are heterozygous for deleterious BRCA1 germline mutations harbor a high risk of hereditary breast cancer. Previous Brca1-heterozygous animal models do not recapitulate the breast cancer phenotype, and thus all currently used knockout models adopt conditional, mammary-specific homozygous Brca1 loss or addition of Trp53 deficiency. Herein, we report the creation and characterization of a novel Brca1 mutant rat model harboring the germline L63X mutation, which mimics a founder mutation in Japan, through CRISPR-Cas9-based genome editing. Homozygotes (Brca1L63X/L63X ) were embryonic lethal, whereas heterozygotes (Brca1L63X/+ ) showed apparently normal development. Without carcinogen exposure, heterozygotes developed mammary carcinoma at a comparable incidence rate with their wild-type (WT) littermates during their lifetime. Intraperitoneal injection of 1-methyl-1-nitrosourea (25 or 50 mg/kg) at 7 weeks of age induced mammary carcinogenesis at comparable levels among the heterozygotes and their littermates. After exposure to ionizing radiation (0.1-2 Gy) at 7 weeks of age, the heterozygotes, but not WT littermates, displayed dose-dependent mammary carcinogenesis with 0.8 Gy-1 excess in hazard ratio during their middle age; the relative susceptibility of the heterozygotes was more prominent when rats were irradiated at 3 weeks of age. The heterozygotes had tumors with a lower estrogen receptor α immunopositivity and no evidence of somatic mutations of the WT allele. The Brca1L63X/+ rats thus offer the first single-mutation, heterozygous model of BRCA1-associated breast cancer, especially with exposure to a DNA break-inducing carcinogen. This implies that such carcinogens are causative and a key to breast cancer prevention in individuals who carry high-risk BRCA1 mutations.

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.

Risk-reducing mastectomy for women with hereditary breast and ovarian cancer (HBOC): analytical results of data from the Japanese Organization of HBOC.

BACKGROUND: Risk-reducing mastectomy is one option for women with hereditary breast and ovarian cancer to reduce the risk of breast cancer. PATIENTS AND METHODS: We analyzed data of the Japanese Organization of Hereditary Breast and Ovarian Cancer on women who were diagnosed as hereditary breast and ovarian cancer by BRCA germline genetic testing between 2010 and 2019 to reveal the rate and likelihood of risk-reducing mastectomy. RESULTS: There were 412 women with BRCA1, 271 with BRCA2 and 4 with both female pathogenic variants. Ninety (13.1%) received risk-reducing mastectomy. The rates of risk-reducing mastectomy were statistically significantly higher in women with BRCA1 pathogenic variants than BRCA2, in women who had breast cancer than those who did not, in women with a breast cancer family history than in those without, in mothers than in those without children, in women who were receiving surveillance with MRI than those who were not and in women who received risk-reducing salpingo-oophorectomy than in those who did not on univariate analyses. The ages when they received the genetic testing were statistically significantly younger in the women receiving risk-reducing mastectomy than those who did not receive it. The women with BRCA1 pathogenic variants, personal history of breast cancer, mothers, those receiving MRI surveillance and younger women were independently significantly more likely to receive risk-reducing mastectomy based on multivariate analysis. CONCLUSIONS: The rate of risk-reducing mastectomy was not high in Japan; however, risk-reducing surgery was approved by the Japanese National Medical Insurance for hereditary breast and ovarian cancer patients with breast and/or ovarian cancer in 2020, so this rate will increase.

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.

The relationship between BRCA-associated breast cancer and age factors: an analysis of the Japanese HBOC consortium database.

BRCA1/2 pathogenic variant prevalence in Japanese breast cancer is unclear. Here, we analyzed BRCA1/2 pathogenic variant prevalence with a particular focus on age factors, using the Japanese HBOC consortium database. All registered subjects were Japanese individuals who underwent BRCA1/2 genetic testing from January 1996 to July 2017 according to the Japanese HBOC consortium database. Cases were extracted and analyzed for each evaluation item. Overall BRCA1 and BRCA2 pathogenic variant prevalence was 11.2% and 9.0% in the cohort of 2366 proband patients, respectively. The age at onset of breast cancer for patients with BRCA1/2 pathogenic variants was significantly lower than that for patients without a BRCA1/2 pathogenic variant. In both BRCA1/2 patients, ages at onset were not statistically significantly different between two subtype groups (ER-positive vs. TNBC). We analyzed the BRCA1/2 pathogenic variant prevalence among age groups in patients with no family history of breast or ovarian cancer. In the TNBC group, the rate of genetic variants was more frequent among younger patients. Our results demonstrated that early breast cancer onset is associated with a BRCA1/2 pathogenic variant in the Japanese population. Younger TNBC patients were more likely to have a BRCA1/2 pathogenic variant irrespective of a family history of breast or ovarian cancer.

Application of targeted nanopore sequencing for the screening and determination of structural variants in patients with Lynch syndrome.

Lynch syndrome is a hereditary disease characterized by an increased risk of colorectal and other cancers. Germline variants in the mismatch repair (MMR) genes are responsible for this disease. Previously, we screened the MMR genes in colorectal cancer patients who fulfilled modified Amsterdam II criteria, and multiplex ligation-dependent probe amplification (MPLA) identified 11 structural variants (SVs) of MLH1 and MSH2 in 17 patients. In this study, we have tested the efficacy of long read-sequencing coupled with target enrichment for the determination of SVs and their breakpoints. DNA was captured by array probes designed to hybridize with target regions including four MMR genes and then sequenced using MinION, a nanopore sequencing platform. Approximately, 1000-fold coverage was obtained in the target regions compared with other regions. Application of this system to four test cases among the 17 patients correctly mapped the breakpoints. In addition, we newly found a deletion across an 84 kb region of MSH2 in a case without the pathogenic single nucleotide variants. These data suggest that long read-sequencing combined with hybridization-based enrichment is an efficient method to identify both SVs and their breakpoints. This strategy might replace MLPA for the screening of SVs in hereditary diseases.

Malignant potential of colorectal neoplasms in Lynch syndrome: an analysis of 325 lesions endoscopically treated at a single institute.

BACKGROUND: Patients with Lynch syndrome are at an increased risk of developing colorectal cancer, and the adenoma-carcinoma sequence is accelerated in these patients. However, the clinicopathological characteristics of colorectal neoplasms in Lynch syndrome patients are not well-known. METHODS: A total of 325 consecutive colorectal neoplasms were endoscopically removed from 68 patients with Lynch syndrome between June 2005 and May 2018 and retrospectively reviewed. RESULTS: Of the 325 lesions, 94 (29%), 220 (68%) and 11 (3%) were from patients with MLH1, MSH2 and MSH6 mutations, respectively. The median lesion size was 5 mm (range 2-40 mm), with 229 (71%) lesions having a non-polypoid morphology. The frequencies of advanced neoplasms, including high-grade adenomas, intramucosal carcinomas and submucosal invasive carcinomas were 14, 34, 97 and 93% for lesions with diameters of <5, ≥5 and <10, ≥10 and <20, and ≥20 mm, respectively. The frequencies of advanced neoplasms in the proximal colon, distal colon and rectum did not significantly differ (36, 35 and 41%, respectively). CONCLUSIONS: Our results suggest that the malignant transformation interval from low-grade adenomas to advanced neoplasms is similar in all parts of the colon. Furthermore, since one-third of neoplastic lesions with diameters of ≥5 and <10 mm and most of those ≥10 mm were advanced neoplasms, we recommend that in Lynch syndrome patients, careful colonoscopic surveillance should be performed throughout the colon, and all neoplastic lesions, regardless of the size, should be subjected to detailed endoscopic examination, complete resection and detailed pathological examination.

Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2020 for the Clinical Practice of Hereditary Colorectal Cancer.

Hereditary colorectal cancer (HCRC) accounts for < 5% of all colorectal cancer cases. Some of the unique characteristics commonly encountered in HCRC cases include early age of onset, synchronous/metachronous cancer occurrence, and multiple cancers in other organs. These characteristics necessitate different management approaches, including diagnosis, treatment or surveillance, from sporadic colorectal cancer management. There are two representative HCRC, named familial adenomatous polyposis and Lynch syndrome. Other than these two HCRC syndromes, related disorders have also been reported. Several guidelines for hereditary disorders have already been published worldwide. In Japan, the first guideline for HCRC was prepared by the Japanese Society for Cancer of the Colon and Rectum (JSCCR), published in 2012 and revised in 2016. This revised version of the guideline was immediately translated into English and published in 2017. Since then, several new findings and novel disease concepts related to HCRC have been discovered. The currently diagnosed HCRC rate in daily clinical practice is relatively low; however, this is predicted to increase in the era of cancer genomic medicine, with the advancement of cancer multi-gene panel testing or whole genome testing, among others. Under these circumstances, the JSCCR guidelines 2020 for HCRC were prepared by consensus among members of the JSCCR HCRC Guideline Committee, based on a careful review of the evidence retrieved from literature searches, and considering the medical health insurance system and actual clinical practice settings in Japan. Herein, we present the English version of the JSCCR guidelines 2020 for HCRC.

The disease sites of female genital cancers of BRCA1/2-associated hereditary breast and ovarian cancer: a retrospective study.

Disease sites of female genital tract cancers of BRCA1/2-associated hereditary breast and ovarian cancer (HBOC) are less understood than non-hereditary cancers. We aimed to elucidate the disease site distribution of genital cancers in women with the germline BRCA1 and BRCA2 pathogenic variants (BRCA1+ and BRCA2+) of HBOC. For the primary disease site, the proportion of fallopian tube and peritoneal cancer was significantly higher in BRCA2+ (40.5%) compared with BRCA1+ (15.4%) and BRCA- (no pathogenic variant, 12.8%). For the metastatic site, the proportion of peritoneal dissemination was significantly higher in BRCA1+ (71.9%) than BRCA- (55.1%) and not different from BRCA2+ (71.4%). With one of the most extensive patients, this study supported the previous reports showing that the pathogenic variants of BRCA1/2 were involved in the female genitalia's disease sites.

Microsatellite instability and mismatch repair protein expressions in lymphocyte-predominant breast cancer.

The frequency of microsatellite instability (MSI) is reportedly extremely low in breast cancer, despite widespread clinical expectations that many patients would be responsive to immune-checkpoint inhibitors (ICI). Considering that some triple-negative breast cancers (TNBC) responded well to ICI in a clinical trial and that a high density of tumor-infiltrating lymphocytes (TILs) is frequently observed in other cancers with high levels of microsatellite instability (MSI-H), we hypothesized that some TNBC with a high density of TILs would be MSI-H. Medullary carcinoma (MedCa) of the breast, a rare histological type, is characterized by a high density of TILs. Considering that MedCa of the colon is often MSI-H, we suspected that MedCa in breast cancer might also include MSI-H tumors. Therefore, we conducted MSI tests on such breast cancers with a high density of TILs. The MSI status of 63 TIL-high TNBC and 38 MedCa tumors, all from Asian women who had undergone curative surgery, were determined retrospectively. DNA mismatch repair (MMR) proteins and PD-L1 expression were also investigated immunohistochemically. All samples were microsatellite stable, being negative for all microsatellite markers. TIL-high TNBC with low MLH1 protein had higher levels of PD-L1 in stromal immune cells (P = .041). MedCa tumors showed significantly higher PD-L1 expression in immune cells than in TIL-high TNBC (<.001). We found that MSI-H tumors were absent in TIL-high breast cancers. Examination of MMR proteins, not a purpose of Lynch syndrome screening, may merit further studies to yield predictive information for identifying patients who are likely to benefit from ICI.