A case of hereditary breast and ovarian cancer syndrome of initially presented as cancer of unknown primary with lymph node metastases unveiled by genetic analysis.

Cancer of unknown primary (CUP) is a heterogeneous disease concept involving various malignant tumors. Understanding its pathophysiology is often difficult, together with its treatment. Here, we present a case of CUP with abdominal lymph node enlargement and elevated carbohydrate antigen 125 levels. It initially resembled a favorable prognosis type similar to ovarian cancer, but metastases were observed in cervical lymph nodes, indicating a somewhat atypical CUP compared to the typical ovarian cancer-like CUP. We identified a germline Breast Cancer 1 (BRCA1) p.L63* variant through a family history inquiry and BRCA analysis, indicating hereditary breast and ovarian cancer syndrome. The patient achieved near-complete remission with platinum-based therapy followed by poly (ADP-ribose) polymerase (PARP) inhibitor. The variant has shown sensitivity in both clinical and pathogenic reports in the ClinVar database of the National Institutes of Health. No clinical studies reported on the efficacy of PARP inhibitors specific to this variant, but our case demonstrated the sensitivity of platinum-based therapy followed by PARP inhibitor. Reports of CUP in hereditary breast and ovarian cancer syndrome are very rare, with only a single report in the literature.

An approach for live imaging of first cleavage in mouse embryos using fluorescent chemical probes for DNA, microtubules, and microfilaments.

Purpose: Dynamic morphological changes in the chromosome and cytoskeleton occur in mammals and humans during early embryonic development, and abnormalities such as embryonic chromosomal aneuploidy occur when development does not proceed normally. Visualization of the intracellular organelles and cytoskeleton allows elucidation of the development of early mammalian embryos. The behavior of the DNA and cytoskeleton in early mammalian embryos has conventionally been observed by injecting target molecule mRNAs, incorporating a fluorescent substance-expressing gene, into embryos. In this study, we visualized the chronological behavior of male and female chromosome condensation in mouse embryos, beginning in the two-pronuclear zygote, through the first division to the two-cell stage, using fluorescent chemical probes to visualize the behavior of DNA, microtubules, and microfilaments. Method: Mouse two-pronuclear stage embryo were immersed in medium containing fluorescent chemical probes to visualize DNA, microtubules, and microfilaments. Observation was performed with a confocal microscope. Results: This method allowed us to observe how chromosome segregation errors in first somatic cell divisions in mouse embryos and enabled dynamic analysis of a phenomenon called lagging chromosomes. Conclusions: By applying this method, we can observe any stage of embryonic development, which may provide new insights into embryonic development in other mammals.

Mesolimbic dopamine release precedes actively sought aversive stimuli in mice.

In some models, animals approach aversive stimuli more than those housed in an enriched environment. Here, we found that male mice in an impoverished and unstimulating (i.e., boring) chamber without toys sought aversive air puffs more often than those in an enriched chamber. Using this animal model, we identified the insular cortex as a regulator of aversion-seeking behavior. Activation and inhibition of the insular cortex increased and decreased the frequencies of air-puff self-stimulation, respectively, and the firing patterns of insular neuron ensembles predicted the self-stimulation timing. Dopamine levels in the ventrolateral striatum decreased with passive air puffs but increased with actively sought puffs. Around 20% of mice developed intense self-stimulation despite being offered toys, which was prevented by administering opioid receptor antagonists. This study establishes a basis for comprehending the neural underpinnings of usually avoided stimulus-seeking behaviors.

Generation of cDC-like cells from human induced pluripotent stem cells via Notch signaling.

BACKGROUND: Dendritic cells (DCs) play critical roles in regulating the innate and adaptive immune responses, and have long been a major focus of cancer immunotherapy. Accumulating evidence suggests that conventional type 1 DCs (cDC1s) excel in cross-presentation of exogenous antigens on MHC-I molecules and induction of antitumor CD8+ T cell immunity; however, obtaining large numbers of cDC1s is difficult. The use of reprogramming and differentiation technology is advantageous for obtaining unlimited numbers of autologous cDC1s especially for therapeutic interventions where repeated vaccinations are required. However, generation of cDC1s from human induced pluripotent stem cells (iPSCs) remains elusive. METHODS: Human iPSCs established from peripheral blood T cells and monocytes were differentiated to myeloid cells under on-feeder or feeder-free culture conditions in vitro. Phenotype, genomic and transcriptomic signature, and function of human iPSC-derived DCs were analyzed. The role of Notch signaling for the generation of HLA-DR+ cells from human iPSCs was interrogated by a loss- and gain-of-function approach. RESULTS: Flow cytometric analyses and single-cell profiling of HLA-DR+ cells revealed that human iPSCs gave rise to CD141+XCR1+CLEC9A+ cells (cDC1s), CLEC4AhiCLEC10A-CD1c+ cells (cDC2As), CLEC4AloCLEC10A+CD1c+ cells (cDC2Bs), CD163-CD5+CD1c+ cells (CD5+cDC2s), and AXL+SIGLEC6+ cells (AS-DCs) on OP9 feeder cells expressing the Notch ligand delta-like 1 (OP9-DL1) while the majority of iPSC-derived cells differentiated on OP9 cells were CD163+CD5-CD1c+ cells (DC3s) and monocytes. Plasmacytoid DCs were not differentiated from iPSCs on either OP9 or OP9-DL1 cells. Inhibition of Notch signaling during co-culture of iPSC-derived CD34+ hematopoietic progenitor cells with OP9-DL1 cells abrogated generation of cDC1s, cDC2As, cDC2Bs, CD5+cDC2s, and AS-DCs but increased frequency of DC3s. Notch-activated human iPSC-derived XCR1+CLEC9A+HLA-DR+CD11c+ cells exhibited similar gene expression profile with peripheral blood cDC1s. Human iPSC-derived DCs have phagocytic, T-cell proliferative, and cytokine-producing functions. CONCLUSIONS: Our study demonstrates a critical role of Notch signaling in regulating developmental pathway of human cDCs. These findings provide insights into the future development of personalized treatment with unlimited numbers of autologous cDCs from human iPSCs.

Consistency between chromosomal status analysis of biopsied human blastocyst trophectoderm cells and whole blastocyst cells.

PURPOSE: This study investigated the consistency between results of preimplantation genetic testing for aneuploidy performed on trophectoderm (TE) cells and remaining blastocyst cells. METHODS: TE biopsy was performed on 29 surplus cryopreserved human blastocysts. Biopsy samples and remaining blastocysts were processed using the VeriSeq PGS kit, and chromosomal statuses were compared by next-generation sequencing. RESULTS: Discordance was observed in the chromosomal status of 11 out of 29 blastocysts between the biopsied TE and remaining blastocysts. Concordance was observed in 11 of 12 blastocysts classified as euploid by TE biopsy and in 7 of 17 blastocysts classified as aneuploid. There was 100% concordance (7/7) in cases diagnosed as aneuploid with no mosaicism by TE biopsy. However, discordance was observed in all 10 cases showing mosaicism or partial chromosomal abnormality. CONCLUSION: Chromosomal status analysis based on TE biopsy does not accurately reflect the chromosomal status of the whole blastocyst. The chromosomal status is usually the same between the TE and remaining blastocyst cells in cases diagnosed as euploid or aneuploid with no mosaicism. However, mosaic blastocysts and those with other types of structural rearrangements have a higher risk of inconsistency, warranting caution during embryo selection.

MLH1 promoter hypermethylation predicts poorer prognosis in mismatch repair deficiency endometrial carcinomas.

OBJECTIVE: The antitumor effects of anti-PD-1 antibody against mismatch repair deficiency (MMR-D)-associated cancers have been reported. MMR-D is found in approximately 20%-30% of endometrial carcinomas (ECs) and frequently occurs due to MLH1 promoter hypermethylation (MLH1-PHM). ECs with MLH1-PHM are classified according to the molecular screening of Lynch syndrome (LS), but few detailed reports are available. The purpose of this study was to clarify the clinical features of EC with MLH1-PHM. METHODS: Immunohistochemistry of MMR proteins (MLH1, MSH2, MSH6, and PMS2) was performed on specimens from 527 ECs treated at our university hospital from 2003 to 2018. MLH1 methylation analysis was added to cases with MLH1/PMS2 loss. ECs were classified as follows: cases that retained MMR proteins as "MMR-proficient;" cases with MLH1/PMS2 loss and MLH1-PHM as "met-EC;" and cases with other MMR protein loss and MLH1/PMS2 loss without MLH1-PHM as "suspected-LS." The clinical features, including long-term prognosis, of each group, were analyzed. RESULTS: Accordingly, 419 (79.5%), 65 (12.3%), and 43 (8.2%) cases were categorized as "MMR-proficient," "suspected-LS," and "met-EC," respectively. Significantly, "met-EC" had a lower proportion of grade 1 tumors (37.5%) and a higher proportion of stage III/IV tumors (37.2%) than the other groups. The overall and progression-free survival of "met-EC" were significantly worse than those of "suspected-LS" in all cases. CONCLUSION: In ECs with MMR-D, "met-ECs" were a subgroup with a poorer prognosis than "suspected-LS." "Met-ECs" would be the main target for anti-PD-1 antibody treatment, and its clinical susceptibility should be verified individually.

In situ delivery of iPSC-derived dendritic cells with local radiotherapy generates systemic antitumor immunity and potentiates PD-L1 blockade in preclinical poorly immunogenic tumor models.

BACKGROUND: Dendritic cells (DCs) are a promising therapeutic target in cancer immunotherapy given their ability to prime antigen-specific T cells, and initiate antitumor immune response. A major obstacle for DC-based immunotherapy is the difficulty to obtain a sufficient number of functional DCs. Theoretically, this limitation can be overcome by using induced pluripotent stem cells (iPSCs); however, therapeutic strategies to engage iPSC-derived DCs (iPSC-DCs) into cancer immunotherapy remain to be elucidated. Accumulating evidence showing that induction of tumor-residing DCs enhances immunomodulatory effect of radiotherapy (RT) prompted us to investigate antitumor efficacy of combining intratumoral administration of iPSC-DCs with local RT. METHODS: Mouse iPSCs were differentiated to iPSC-DCs on OP9 stromal cells expressing the notch ligand delta-like 1 in the presence of granulocyte macrophage colony-stimulating factor. Phenotype and the capacities of iPSC-DCs to traffic tumor-draining lymph nodes (TdLNs) and prime antigen-specific T cells were evaluated by flow cytometry and imaging flow cytometry. Antitumor efficacy of intratumoral injection of iPSC-DCs and RT was tested in syngeneic orthotopic mouse tumor models resistant to anti-PD-1 ligand 1 (PD-L1) therapy. RESULTS: Mouse iPSC-DCs phenotypically resembled conventional type 2 DCs, and had a capacity to promote activation, proliferation and effector differentiation of antigen-specific CD8+ T cells in the presence of the cognate antigen in vitro. Combination of in situ administration of iPSC-DCs and RT facilitated the priming of tumor-specific CD8+ T cells, and synergistically delayed the growth of not only the treated tumor but also the distant non-irradiated tumors. Mechanistically, RT enhanced trafficking of intratumorally injected iPSC-DCs to the TdLN, upregulated CD40 expression, and increased the frequency of DC/CD8+ T cell aggregates. Phenotypic analysis of tumor-infiltrating CD8+ T cells and myeloid cells revealed an increase of stem-like Slamf6+ TIM3- CD8+ T cells and PD-L1 expression in tumor-associated macrophages and DCs. Consequently, combined therapy rendered poorly immunogenic tumors responsive to anti-PD-L1 therapy along with the development of tumor-specific immunological memory. CONCLUSIONS: Our findings illustrate the translational potential of iPSC-DCs, and identify the therapeutic efficacy of a combinatorial platform to engage them for overcoming resistance to anti-PD-L1 therapy in poorly immunogenic tumors.

Cell-free DNA in spent culture medium effectively reflects the chromosomal status of embryos following culturing beyond implantation compared to trophectoderm biopsy.

This prospective study evaluated the accuracy of non-invasive preimplantation genetic testing for aneuploidy (niPGT-A) using cell-free DNA in spent culture medium, as well as that of preimplantation genetic testing for aneuploidy (PGT-A) using trophectoderm (TE) biopsy after culturing beyond implantation. Twenty frozen blastocysts donated by 12 patients who underwent IVF at our institution were investigated. Of these, 10 were frozen on day 5 and 10 on day 6. Spent culture medium and TE cells were collected from each blastocyst after thawing, and the embryos were cultured in vitro for up to 10 days. The outgrowths after culturing beyond implantation were sampled and subjected to chromosome analysis using next-generation sequencing. Chromosomal concordance rate, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), false-positive rate (FPR), and false-negative rate (FNR) of niPGT-A and PGT-A against each outgrowth were analyzed. The concordance rate between the niPGT-A and outgrowth samples was 9/16 (56.3%), and the concordance rate between the PGT-A and outgrowth samples was 7/16 (43.8%). NiPGT-A exhibited 100% sensitivity, 87.5% specificity, 88.9% PPV, 100% NPV, 12.5% FPR, and 0% FNR. PGT-A exhibited 87.5% sensitivity, 77.8% specificity, 87.5% PPV, 75% NPV, 14.3% FPR, and 22.2% FNR. NiPGT-A may be more accurate than PGT-A in terms of ploidy diagnostic accuracy in outgrowths.

Detection of MED12 mutations in mesenchymal components of uterine adenomyomas.

Adenomyoma of the uterus is a biphasic nodular lesion composed of a mesenchymal component with smooth muscle differentiation and a glandular epithelium. The neoplastic nature of uterine adenomyomas has been controversial because some are considered to be nodular adenomyosis. MED12 mutations are involved in the pathogenesis of uterine smooth muscle tumors (leiomyomas and leiomyosarcomas) and biphasic tumors of the breast (fibroadenomas and phyllodes tumor). To investigate the histogenesis of uterine adenomyomas, we performed pathological and genetic analyses, including Sanger sequencing of MED12. In total, 15 cases of uterine adenomyomas were retrieved and assessed for clinicopathological factors. Immunohistochemistry for smooth muscle actin, desmin, and CD10 was performed. Exon 2 of MED12 was Sanger sequenced using DNA obtained by macrodissection of the adenomyomas. For cases that were positive for somatic MED12 mutations, we next performed microdissection of the mesenchymal and epithelial components. The DNA extracted from each component was further analyzed for MED12 mutations. MED12 mutations were detected in two adenomyomas (2/15, 13%), all in a known hot spot (codon 44). In both lesions, MED12 mutations were detected in multiple spots of the mesenchymal component. The epithelial component did not harbor MED12 mutations. The relatively low frequency of MED12 mutations suggests that not all adenomyomas are leiomyomas with entrapped glands. However, the results of our study suggest that a subset of uterine adenomyomas are true mesenchymal neoplasms.

Detection of MEAF6-PHF1 translocation in an endometrial stromal nodule.

Endometrial stromal nodule (ESN) and low-grade endometrial stromal sarcoma (LG-ESS) are rare uterine tumors known as endometrial stromal tumors (ESTs). In addition to their similarity in morphological features, recent studies have shown that these two tumors share common genetic alterations. In particular, JAZF1-SUZ12 fusion is found with high frequency in both ESN and LG-ESS. In LG-ESS, some minor fusions have also been described, which include rearrangements involving PHF1 and its partner genes, such as JAZF1, EPC1, MEAF6, BRD8, EPC2, and MBTD1. Because of the rarity of ESN, genetic alterations other than JAZF1 fusion have not been investigated in detail. In this study, we performed a next-generation sequencing-based analysis in a case of ESN with peripheral metaplastic bone formation and detected MEAF6-PHF1 fusion, which has been reported in a small subset of uterine LG-ESSs and soft tissue ossifying fibromyxoid tumors. The finding that MEAF6-PHF1 fusion is a background genetic abnormality detected both in ESN and LG-ESS, along with JAZF1-SUZ12, provides further support for the similarity and continuum between these two types of ESTs. Furthermore, the association between metaplastic bone formation and MEAF6-PHF1 fusion may not be limited to soft tissue tumors.

Kinetics of meiotic maturation in oocytes from unstimulated ovaries and duration of pronucleus presence and preimplantation development.

OBJECTIVE: To evaluate the meaning of meiotic maturation kinetics and duration of pronucleus presence (DPP) for parthenogenetic activation outcome. DESIGN: Retrospective study. SETTING: University hospital. PATIENT(S): Eight patients with endometrioid adenocarcinoma and 65 patients who underwent in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI). INTERVENTION(S): After collection of oocytes from nonstimulated ovaries of patients with endometrioid adenocarcinoma, in vitro maturation (IVM) and parthenogenetic activation performed with time-lapse imaging; after ICSI, embryos similarly incubated with time-lapse imaging. MAIN OUTCOME MEASURE(S): Timing of the release of the first polar body (fPB), DPP, and developmental stage with IVM and parthenogenetic activation; after ICSI, assessment of DPP and preimplantation developmental stage. RESULT(S): With IVM, 55.2% of oocytes matured; 53.1% of fPBs were released within 24 hours, and 46.9% of fPBs were released after 24 hours. Regarding developmental stage, oocytes that released fPB later during IVM tended to develop more than oocytes that released the fPB within 24 hours. For embryos from parthenogenetic activation the DPP was statistically significantly shorter than the DPP of embryos from ICSI. With ICSI, the DPP was statistically significantly shorter in embryos that developed to ≥8 cells than embryos whose final development included ≤7 cells. The development rate in parthenogenetic activation was statistically significantly lower than that in ICSI. CONCLUSION(S): Embryo development is negatively affected by DPP that is too short or too long. When the DPP was short with parthenogenetic activation, embryo development did not proceed, indicating that DPP is an important determinant of parthenogenetic activation outcomes as with the timing of fPB release.

[Learning Paradigms for the Promotion of Memory, and Their Underlying Principles].

Efficient learning is essential for the activities of everyday life, such as for school and business. This review summarizes the effect of sleep and its timing, as well as the effect of napping and rest, on learning efficiency. In addition, we compare various learning methods, including specific versus varied practice and blocked versus interleaved learning, and propose daily techniques for efficient learning.

Answering hastily retards learning.

Appropriate decisions involve at least two aspects: the speed of the decision and the correctness of the decision. Although a quick and correct decision is generally believed to work favorably, these two aspects may be interdependent in terms of overall task performance. In this study, we scrutinized learning behaviors in an operant task in which rats were required to poke their noses into either of two holes by referring to a light cue. All 22 rats reached the learning criterion, an 80% correct rate, within 4 days of testing, but they were diverse in the number of sessions spent to reach the learning criterion. Individual analyses revealed that the mean latency for responding was negatively correlated with the number of sessions until learning, suggesting that the rats that responded more rapidly to the cues learned the task more slowly. For individual trials, the mean latency for responding in correct trials (LC) was significantly longer than that in incorrect trials (LI), suggesting that, on average, long deliberation times led to correct answers in the trials. The success ratio before learning was not correlated with the learning speed. Thus, deliberative decision-making, rather than overall correctness, is critical for learning.

Hippocampal ripples down-regulate synapses.

The specific effects of sleep on synaptic plasticity remain unclear. We report that mouse hippocampal sharp-wave ripple oscillations serve as intrinsic events that trigger long-lasting synaptic depression. Silencing of sharp-wave ripples during slow-wave states prevented the spontaneous down-regulation of net synaptic weights and impaired the learning of new memories. The synaptic down-regulation was dependent on the N-methyl-d-aspartate receptor and selective for a specific input pathway. Thus, our findings are consistent with the role of slow-wave states in refining memory engrams by reducing recent memory-irrelevant neuronal activity and suggest a previously unrecognized function for sharp-wave ripples.

Clinical characteristics of Lynch-like cases collaterally classified by Lynch syndrome identification strategy using universal screening in endometrial cancer.

OBJECTIVE: Lynch syndrome (LS), an autosomal-dominant inherited disorder, increases the risk for LS-associated cancers (LS-AC). Molecular LS assessment for all cases is referred to as universal screening (U/S) and is recommended for endometrial cancer (EC) and colorectal cancer. Lynch-like cases (LL) lack LS-pathogenic mutations despite being suspected as LS by U/S, but have been poorly investigated in EC. The aim of this study was to capture the features of LL in EC and to devise LL management in EC. METHODS: U/S, consisting of immunohistochemistry and reflex methylation analysis, was applied to 348 Asian ECs, and sporadic cancer (SC) cases were screened out. Genetic testing was offered to "suspected-LS" cases selected by U/S. The features of the LS, LL, and SC groups were recorded and compared. RESULTS: U/S screened 306 ECs as SC. The recurrence rates of suspected-LS and SC cases were 14.3% (6/42) and 26.5% (81/306), respectively. Of the 42 suspected-LS cases, 10 were identified as LS, 17 were classified as LL, and 15 did not undergo genetic testing. In the LS group, the frequency of personal history (50%) and family history (100%) of LS-AC were prominent. Of note, the prevalence of family history of LS-AC and gastric cancer was significantly higher in the LL group than in the SC group (76.5% vs. 38.6% and 47.1% vs. 25.2%, respectively). CONCLUSIONS: Herein, we report the features of LL classified by LS identification via U/S in Asian EC. LL should be candidates for tailored surveillance based on regionality and family history.

Cesarean scar caseating granuloma: a case of vesicouterine fistula 30 years after cesarean section.

A mass developing in operating scar part with fistula should raise concern for caseating granuloma even if many years after operation.

Perinatal Management of Pregnancy Complicated by Autosomal Dominant Emery-Dreifuss Muscular Dystrophy.

Introduction Autosomal dominant Emery-Dreifuss muscular dystrophy (AD-EDMD) is rare compared with other forms of muscular dystrophy and is characterized by cardiac conduction defects. Here, we present the case of a patient diagnosed with AD-EDMD during the first trimester of pregnancy who developed acute preeclampsia and subsequently, congestive heart failure (CHF) following cesarean section. Case A 36-year-old, gravida 0 para 0 woman was diagnosed with AD-EDMD by genetic testing during the first trimester of pregnancy, and she suddenly developed preeclampsia and partial HELLP (hemolytic anemia, elevated liver enzymes, and low platelets) syndrome at 33 weeks of gestation. The patient subsequently developed CHF following cesarean section. Conclusion CHF can occur as a direct result of the cardiac defects arising due to EDMD, and therefore, careful prenatal and postpartum management is recommended for such cases.

Prediction of spontaneous vaginal delivery by transperineal ultrasound performed just after full cervical dilatation is determined.

PURPOSE: To investigate whether transperineal ultrasound examination just after full cervical dilatation is determined can predict the mode of delivery. METHODS: This was a prospective observational study of pregnant women. After full cervical dilatation was determined by vaginal examination during labor, transperineal ultrasound was immediately performed, and the head direction (HD), progression distance (PD), and angle of progression (AoP) were measured. The cases were divided into two groups: spontaneous vaginal delivery and operative delivery due to failure of progression. Differences between the groups were statistically analyzed using Student's t test and Fisher's exact test. RESULTS: Of the 50 women, 42 had spontaneous vaginal deliveries and 8 had vacuum extractions. The spontaneous delivery group had significantly higher HD, PD, and AoP values than the vacuum extraction group. The areas under the receiver-operating characteristic curves for the prediction of spontaneous vaginal delivery were 0.850 for HD, 0.827 for PD, and 0.783 for AoP. The optimum cut-off points and positive predictive values were 83° and 92.9 % for HD, 56 mm and 94.9 % for PD, and 146° and 94.3 % for AoP, respectively. CONCLUSION: Transperineal ultrasound examination just after full cervical dilatation was determined was useful in predicting spontaneous vaginal delivery.

Isolated Loss of PMS2 Immunohistochemical Expression is Frequently Caused by Heterogenous MLH1 Promoter Hypermethylation in Lynch Syndrome Screening for Endometrial Cancer Patients.

Lynch syndrome (LS) is an autosomal-dominant inherited disorder mainly caused by a germline mutation in the DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6, and PMS2) and is associated with increased risk for various cancers, particularly colorectal cancer and endometrial cancer (EC). Women with LS account for 2% to 6% of EC patients; it is clinically important to identify LS in such individuals for predicting and/or preventing additional LS-associated cancers. PMS2 germline mutation (PMS2-LS) is the rarest contribution to LS etiology among the 4 LS-associated MMR germline mutations, and its detection is complicated. Therefore, prudent screening for PMS2-LS is important as it leads to an efficient LS identification strategy. Immunohistochemistry is recommended as a screening method for LS in EC. Isolated loss of PMS2 (IL-PMS2) expression is caused not only by PMS2-LS but also by MLH1 germline mutation or MLH1 promoter hypermethylation (MLH-PHM). This study aimed to determine the association between MLH1-PHM and IL-PMS2 to avoid inappropriate genetic analysis. We performed MLH1 methylation analysis and MLH1/PMS2 germline mutation testing on the IL-PMS2 cases. By performing MMR-immunohistochemistry on 360 unselected ECs, we could select 8 (2.2%) cases as IL-PMS2. Heterogenous MLH1 staining and MLH1-PHM were detected in 4 of 8 (50%) IL-PMS2 tumors. Of the 5 IL-PMS2 patients who underwent genetic analysis, 1 had PMS2 germline mutation with normal MLH1 expression (without MLH1-PHM), and no MLH1 germline mutation was detected. We suggest that MLH1 promoter methylation analysis for IL-PMS2 EC should be performed to exclude sporadic cases before further PMS2 genetic testing.