Morphoproteomic analysis reveals an overexpressed and constitutively activated phospholipase D1-mTORC2 pathway in endometrial carcinoma

The mammalian target of rapamycin (MTOR) assembles into two distinct complexes: mTOR complex 1 (mTORC1) is predominantly cytoplasmic and highly responsive to rapamycin, whereas mTOR complex 2 (mTORC2) is both cytoplasmic and nuclear, and relatively resistant to rapamycin. mTORC1 and mTORC2 phosphorylatively regulate their respective downstream effectors p70S6K/4EBP1, and Akt. The resulting activated mTOR pathways stimulate protein synthesis, cellular proliferation, and cell survival. Moreover, phospholipase D (PLD) and its product, phosphatidic acid (PA) have been implicated as one of the upstream activators of mTOR signaling. In this study, we investigated the activation status as well as the subcellular distribution of mTOR, and its upstream regulators and downstream effectors in endometrial carcinomas (ECa) and non-neoplastic endometrial control tissue. Our data show that the mTORC2 activity is selectively elevated in endometrial cancers as evidenced by a predominant nuclear localization of the activated form of mTOR (p-mTOR at Ser2448) in malignant epithelium, accompanied by overexpression of nuclear p-Akt (Ser473), as well as overexpression of vascular endothelial growth factor (VEGF)-A isoform, the latter a resultant of target gene activation by mTORC2 signaling via hypoxia-inducible factor (HIF)-2alpha. In addition, expression of PLD1, one of the two major isoforms of PLD in human, is increased in tumor epithelium. In summary, we demonstrate that the PLD1/PA-mTORC2 signal pathway is overactivated in endometrial carcinomas. This suggests that the rapamycin-insensitive mTORC2 pathway plays a major role in endometrial tumorigenesis and that therapies designed to target the phospholipase D pathway and components of the mTORC2 pathway should be efficacious against ECa.     

人子宫内膜癌中p57 kip2、Cyclin D1的表达及意义

目的：探讨p57 kip2、Cyclin D1在人子宫内膜癌发生、发展中的作用。方法选取子宫内膜样腺癌( endometrioid adenocar-cinoma, EA)100例、子宫内膜上皮内瘤变(endometrial intraepithelial neoplasia, EIN)20例、子宫内膜增生性病变20例、增生期子宫内膜组织20例;选取不同子宫内膜细胞[高分化子宫内膜癌细胞( Ishikawa)、中分化子宫内膜癌细胞( JEC)、低分化子宫内膜癌细胞(KLE)及正常子宫内膜细胞(ESC)]进行细胞培养。应用免疫组化EliVision法检测不同子宫内膜组织中p57kip2、Cyclin D1蛋白的表达;Western blot法检测不同子宫内膜细胞中p57 kip2、Cyclin D1蛋白的表达。结果 p57 kip2蛋白在EIN组织中表达最高,在增生期子宫内膜、EA、子宫内膜增生性病变组织中表达逐渐降低,子宫内膜增生性病变与EIN组织中p57 kip2蛋白表达差异有统计学意义(P<0.05)。 Cyclin D1蛋白在EA组织中表达最高,在增生期子宫内膜组织中表达最低,在子宫内膜增生性病变组织、EIN组织中表达依次增高,差异均有显著性( P<0.01)。 p57 kip2、Cyclin D1蛋白在EA组织中的表达随着组织学分级的增高呈依次递减趋势,但仅p57 kip2蛋白表达和组织学分级有关( P<0.05)。 p57 kip2蛋白在KLE中表达最高,在ESC中表达最低,两组相比差异有显著性( P<0.05);Cyclin D1在JEC、Ishikawa中的表达高于ESC,差异均有显著性( P<0.05)。结论 p57kip2、Cyclin D1均参与子宫内膜癌的发生、发展。 Cyclin D1表达是子宫内膜癌发生的早期事件,可能还存在异常合成的p57 kip2蛋白,其协同Cyclin D1促进子宫内膜的恶性转化。联合检测p57 kip2、Cyclin D1在子宫内膜癌中的表达,对预测子宫内膜癌患者预后有一定的临床意义。     

Morphoproteomic and molecular concomitants of an overexpressed and activated mTOR pathway in renal cell carcinomas

CCI-779 (temsirolimus), an ester of rapamycin and an inhibitor of the mammalian target of rapamycin (mTOR), is currently in phase II trials for treatment of patients with solid cancers. The mTOR functions as a checkpoint for cell proliferation, with upstream Akt and downstream p70S6K serving as its most important mediators. The aim of this study was to evaluate the expression and activation of the Akt-mTOR-p70S6K pathway in renal cell carcinoma (RCC), seeking to strengthen the rationale for targeted therapy of RCC using rapamycin or a rapamycin analogue. Tissue microarray sections containing 128 primary RCCs, 22 metastatic RCCs, and 24 non-neoplastic (normal) kidneys (NK) were immunostained with monoclonal antibodies to phosphorylated (p)-Akt (Ser473), p-mTOR (Ser2448), and p-p70S6K (Thr389). Western blotting was performed on 3 cases of clear cell RCC (CRCC) and the corresponding non-neoplastic (normal) renal tissues using the same antibodies. The immunostain scoring system included: (a) location; (b) distribution; and (c) intensity. The normal kidneys provided baseline scores for comparison. Expression of p-Akt, p-mTOR, and p-p70S6K was seen in 100% (n = 24) of NKs and nearly 100% (n = 150) of both primary and metastatic RCCs. The p-p70S6K was located in the nucleus in both NKs and RCCs. The p-Akt was observed in the nucleus and cytoplasm of NKs and in the nucleus and cytoplasm/ membrane (plasmalemma) of RCCs. The p-mTOR was identified in the membrane of NKs and the membrane/nucleus of RCCs. The levels of expression of p-p70S6K, p-mTOR, and p-Akt were significantly higher in RCC than in NK in the overall pattern (intensity and distribution, p <0.05). Western blotting also showed higher expression of p-p70S6K, p-mTOR, and p-Akt in RCCs compared to the corresponding normal kidney tissues (p <0.05). These findings indicate that correlative over-expression and activation of p-Akt, p-mTOR, and p-p70S6K are commonly observed in RCCs. After considering these findings in the context of other established protein circuitries and pathways in RCC, we propose therapeutic approaches that incorporate rapamycin-like agents and other small molecule inhibitors in a combinatorial fashion in future clinical trials for RCC.     

Subtype-specific mutation of PPP2R1A in endometrial and ovarian carcinomas

PPP2R1A mutations have recently been described in 3/42 (7%) of clear cell carcinomas of the ovary. PPP2R1A encodes the α-isoform of the scaffolding subunit of the serine/threonine protein phosphatase 2A (PP2A) holoenzyme. This putative tumour suppressor complex is involved in growth and survival pathways. Through targeted sequencing of PPP2R1A, we identified somatic missense mutations in 40.8% (20/49) of high-grade serous endometrial tumours, and 5.0% (3/60) of endometrial endometrioid carcinomas. Mutations were also identified in ovarian tumours at lower frequencies: 12.2% (5/41) of endometrioid and 4.1% (2/49) of clear cell carcinomas. No mutations were found in 50 high-grade and 12 low-grade serous carcinomas. Amino acid residues affected by these mutations are highly conserved across species and are involved in direct interactions with regulatory B-subunits of the PP2A holoenzyme. PPP2R1A mutations in endometrial high-grade serous carcinomas are a frequent and potentially targetable feature of this disease. The finding of frequent PPP2R1A mutations in high-grade serous carcinoma of the endometrium but not in high-grade serous carcinoma of the ovary provides clear genetic evidence that these are distinct diseases.     

GLUT1 and p63 expression in endometrial intraepithelial and uterine serous papillary carcinoma

AIMS: To analyse the expression patterns of GLUT1, p63 and p53 and the possible correlation between these markers in uterine serous papillary carcinoma (USPC) and endometrial intraepithelial carcinoma (EIC). METHODS AND RESULTS: Fourteen cases of USPC, 12 of which also showed EIC, were examined for GLUT1, p63 and p53 immunoreactivity. Four-micrometre sections from formalin-fixed paraffin-embedded tissue were immunostained using commercially available primary antibodies and Dako Envision Plus reagents for visualization. Membranous GLUT1 immunoreactivity was observed in all cases, including all 14 invasive tumours (100%) and 11 of 12 associated EICs (92%), and was confined to neoplastic cells. In USPC, staining tended to be strongest in superficial antistromal regions. p63 positivity was found in 8/14 (57%) USPCs and 9/12 (75%) associated EICs. In 11 cases p53 was overexpressed in both invasive USPC (11/14; 79%) and EIC (11/12; 92%). p53+ USPCs tended to be positive for p63, whereas p53- USPCs were also negative for p63. CONCLUSIONS: GLUT1 is expressed in the vast majority of USPC and EIC, suggesting a biological role during the early steps of carcinogenesis in endometrial serous neoplasms. GLUT1 expression may be induced by hypoxia-related as well as other mechanisms.     

Nuclear and cytoplasmic bcl-2 expression in endometrial hyperplasia and adenocarcinoma

The bcl-2 proto-oncogene, which inhibits programmed cell death (apoptosis), has recently been found to be cyclically expressed in human endometrium. In order to investigate its role in endometrial hyperlasia and neoplasia, bcl-2 expression was studied in 25 cases of endometrial carcinoma and 20 cases of endometrial hyperplasia (eight simple, two complex, and ten atypical hyperplasias). Uniform intense cytoplasmic bcl-2 expression was found in all cases of non-atypical hyperplasia, and less strong positivity in eight out of ten cases of atypical hyperplasia. In well-differentiated carcinomas, nine out of ten showed weak to moderate bcl-2 expression, whereas six out of seven poorly differentiated carcinomas were bcl-2-negative. Moderately differentiated tumours were an intermediate group, with six out of eight being positive. Widespread localization of bcl-2 protein to the chromosomes of dividing cells was also demonstrated, regardless of cytoplasmic bcl-2 expression, with rare staining of interphase nuclei. Our findings suggest a role for bcl-2 in the natural history of endometrial neoplasia and studies are needed to determine its usefulness as a prognostic marker. The finding of bcl-2 localization to chromosomes has important implications for its mode and site of action.     

MiR-218 inhibits HMGB1-mediated autophagy in endometrial carcinoma cells during chemotherapy

Endometrial carcinoma is the most common gynecological malignancy among women worldwide. Although treatment for EC has improved with the introduction of Paclitaxel (Tax) chemotherapy, the majority of patients will develop resistance to the treatment, leading to poor prognosis. One of the causes of chemoresistance is the increased ability to undergo autophagy. In this study, we identified that miR-218 was significantly down-regulated in Tax-resistant EC cells compared to the non-drug resistant cell lines, and overexpression of miR-218 sensitized paclitaxel resistant EC cells to paclitaxel. Moreover, we demonstrated that miR-218 directly binds to the 3’-UTR of HMGB1 gene. HMGB1 was upregulated in paclitaxel resistant EC cells, it mediated autophagy and contributed to chemotherapy resistance in endometrial carcinoma in vitro. HMGB1-mediated autophagy could be suppressed by miR-218 overexpression in Tax resistant EC cells. In summary, we determined the targeting role of miR-218 to HMGB1 and the regulation of miR-218 on the HMGB1-mediated cell autophagy during chemotherapy resistance in endometrial carcinoma cells. These results reveal novel potential role of miR-218 against chemotherapy resistance during the treatment of endometrial carcinoma.     

KPNA2 is overexpressed in human and mouse endometrial cancers and promotes cellular proliferation

Endometrial cancer is the most frequently occurring malignancy of the female genital tract in Western countries. Although in many cases surgically curable, about 30% of the tumours represent an aggressive and untreatable disease. In an attempt to establish a reliable prognostic marker for endometrial carcinomas disregarding their histological diversity, we investigated the expression of KPNA2, a mediator of nucleocytoplasmic transport, and other cell proliferation‐associated proteins and their correlation with cancer progression. We analysed patient tissue microarrays (TMAs) assembled from 527 endometrial cancer tissue specimens and uterus samples from a Trp53 knockout mouse model of endometrial cancer. Our data show that KPNA2 expression was significantly up‐regulated in human endometrial carcinomas and associated with higher tumour grade (p = 0.026), higher FIGO stage (p = 0.027), p53 overexpression (p < 0.001), activation of the PI3K/AKT pathway, and epithelial–mesenchymal transition. Increased nuclear KPNA2 immunoreactivity was identified as a novel predictor of overall survival, independent of well‐established prognostic factors in Cox regression analyses (hazard ratio 1.7, 95% CI 1.13–2.56, p = 0.01). No significant association between KPNA2 expression and endometrial cancer subtype was detected. In the mouse model, KPNA2 showed increased expression levels from precancerous (EmgD, EIC) to far‐advanced invasive lesions. We further investigated the cell proliferation capacity after siRNA‐mediated KPNA2 knockdown in the human endometrial cancer cell line MFE‐296. KPNA2 silencing led to decreased proliferation of the cancer cells, suggesting interplay of the protein with the cell cycle. Taken together, increased expression of KPNA2 is an independent prognostic marker for poor survival. The mechanism of enhanced nucleocytoplasmic transport by KPNA2 overexpression seems a common event in aggressive cancers since we have shown a significant correlation of KPNA2 expression and tumour aggressiveness in a large variety of other solid tumour entities. Introducing KPNA2 immunohistochemistry in routine diagnostics may allow for the identification of patients who need more aggressive treatment regimens. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd     

Oestrogen receptor gene (ESR1) amplification is frequent in endometrial carcinoma and its precursor lesions

Oestrogen receptor alpha (ER) plays a critical, diverse and not fully understood role in endometrial carcinoma. Most endometrial carcinomas express ER and some of these tumours respond favourably to anti-oestrogen therapy. On the other hand, tamoxifen therapy constitutes a major risk factor for endometrial carcinoma development. Amplification of the ESR1 gene encoding ER was recently shown to constitute a mechanism for ER over-expression in breast carcinoma. This study was designed to determine the potential role of ESR1 amplifications in endometrial carcinoma. Tissue microarrays of 368 endometrial carcinomas and large sections of 43 cases of endometrial hyperplasia were analysed for ESR1 gene amplification and ER protein expression by means of fluorescence in situ hybridization (FISH) and immunohistochemistry. FISH revealed ESR1 amplification in 40/176 (23%) cancers, 6/19 (32%) atypical complex hyperplasias, 3/10 (30%) complex hyperplasias without atypia and 2/14 (14%) simple hyperplasias without atypia. Strong ER protein expression was significantly linked to ESR1 amplification in endometrial carcinoma (p = 0.0036). These data indicate that ESR1 amplification might be one mechanism for ER over-expression in endometrial carcinoma, and suggest an early role for ESR1 amplification in the development of a significant fraction of endometrial carcinoma. Given the predictive role of ESR1 amplification for tamoxifen response in breast carcinoma, it will be interesting to investigate the response of ESR1-amplified endometrial cancers to anti-oestrogenic drugs. Copyright (c) 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

子宫内膜癌淋巴结转移的危险因素及预后分析

目的探讨子宫内膜癌腹膜后淋巴结转移的高危因素及淋巴结转移对于预后的影响。方法回顾性分析2005年1月至2010年12月期间在北京协和医院妇产科进行诊治的289例行腹膜后淋巴结切除的子宫内膜癌患者的临床病理资料,对影响子宫内膜癌腹膜后淋巴结转移的高危因素和影响子宫内膜癌患者预后的因素进行统计分析。结果 1)289例患者中位发病年龄55岁,Ⅰ期224例(77.5%),Ⅱ期13例(4.5%),Ⅲ期45例(15.6%),Ⅳ期7例(2.4%)。289例行盆腔淋巴结切除,30例(10.4%)有盆腔淋巴结转移;96例行腹主动脉旁淋巴结切除,11例(11.5%)有腹主动脉旁淋巴结转移。复发21例(7.3%),死亡11例(3.8%),中位随访时间37个月,中位无瘤生存时间34个月。2)单因素分析显示术前CA125≥35 U/m L、非子宫内膜样癌、组织学分级为G3、深肌层浸润、肿瘤≥2 cm、宫颈间质受累、腹腔冲洗液细胞学阳性及阴道或宫旁受累是淋巴结转移率的高危因素(P0.05)。多因素分析显示术前CA125值≥35 U/m L、低分化、肌层浸润深度≥1/2是淋巴结转移的独立危险因素(P0.05)。3)Kaplan-Meier单因素分析显示,腹腔冲洗液细胞学阳性、阴道或宫旁受累、附件受累及淋巴结转移缩短无瘤生存时间(P0.05);非子宫内膜样癌、低分化、肌层浸润深度≥1/2、腹腔冲洗液细胞学阳性、附件受累及淋巴结转移缩短总生存时间(P0.05)。COX回归多因素分析显示,腹膜后淋巴结转移是5年无瘤生存率的独立预后因素(未转移者92.1%vs转移者65.3%,P=0.002,95%CI 0.078~0.552);虽不是5年总生存率的独立预后因素,但无淋巴结转移者的5年总生存率有高于淋巴结转移者的趋势(未转移者96.1%vs转移者70.0%,P=0.086,95%CI 0.039~1.238)。结论本研究发现:1)肿瘤分化程度和肌层浸润深度对淋巴结转移有预测意义,能够指导子宫内膜癌患者是否进行淋巴结切除术,为个体化治疗奠定理论基础。2)淋巴结转移患者仍然有较无淋巴结转移者预后更差的趋势,因此对于淋巴结转移的患者需要进行辅助治疗,减少复发风险。     

CARLo-5 as an oncogenic gene in endometrial carcinoma

The long noncoding RNA CARLo-5 is dysregulated in multiple types of human cancers. High CARLo-5 is a promising predictive factor for various cancers, including endometrial carcinoma (EC). Our previous study showed that the expression level of CARLo-5 was associated with advanced FIGO stage (The International Federation of Gynecology and Obstetrics), lymph node metastasis, and the poor survival of patients with EC. In the present study, we demonstrated that the downregulation of CARLo-5 could affect the proliferation, cell cycle, migration, and invasion of EC cell lines HEC-1B and KLE cells. The oncogenic activity of CARLo-5 was also confirmed with in vivo data. Mechanistically, CARLo-5 could affect the expression of CDK/CDKN1A and MMP2/9, which have been reported to be regulated by CARLo-5 and associated with cell cycle and motility. In conclusion, this study is the first to discover the biological function and mechanism of CARLo-5 in regulating the biological characteristics of EC cells. Targeting CARLo-5 and its pathway might provide new biomarkers or potential therapies target for patients with EC. Environ. Mol. Mutagen. 61:256–265, 2020. © 2019 Wiley Periodicals, Inc.     

The role of matrix metalloproteinases-2, -7 and -9 and beta-catenin in high grade endometrial carcinoma

AIMS: To determine the expression of matrix metalloproteinases (MMPs)-2, -7 and -9 and beta-catenin in uterine serous carcinoma (USC) and endometrioid endometrial carcinoma (EEC) and to investigate any difference in expression between EEC and USC which might explain the mechanism of invasion and aggressive behaviour of USC. METHODS AND RESULTS: Tissue microarrays were created from the viable central part and from the invasive edge of 20 cases of grade 3 EEC and 73 cases of USC. Immunohistochemistry was performed using antibodies to MMPs-2, -7 and -9 and beta-catenin. MMPs-2, -7 and -9 and beta-catenin were present in both tumour types; there was significantly higher expression of MMPs-2 and -9 in EEC compared with USC and significantly increased expression of MMPs-2 and -9 by carcinoma cells at the invasive edge of USC. CONCLUSIONS: MMPs-2, -7 and -9 and beta-catenin are present in EEC and USC. The increased expression of MMPs-2 and -9 by carcinoma cells at the invasive edge of USC is possibly due to increased binding of MMPs secreted by the stromal cells to carcinoma cells, thus equipping the USC carcinoma cells with proteases for invasion.     

CyclinD1和PCNA在子宫内膜癌中表达及临床意义

目的探讨CycliD1和PCNA在子宫内膜癌中的表达及临床意义。方法应用免疫组化法检测50例子宫内膜癌,22例子宫内膜不典型增生和8例正常子宫内膜中CyclinD1,PCNA的表达。结果 CyclinD1和PCNA在子宫内膜癌中的阳性表达率分别为54%(27/50)和68%(34/50),明显高于正常子宫内膜组(P0.05)。子宫内膜癌中,CyclinD1的表达与FIGO分期和淋巴结转移密切相关(P0.05),PCNA的表达与病理分级和淋巴结转移密切相关(P0.05)。相关性分析显示,CyclinD1和PCNA在子宫内膜癌中的表达呈正相关(r=0.742,P0.05)。二者协同异常表达者生物学行为较好。结论 CyclinD1和PCNA可能在子宫内膜癌发生发展中起重要作用,可作为评估预后的指标。     

Uterine serous carcinoma and endometrial intraepithelial carcinoma arising in endometrial polyps: report of 5 cases, including 2 associated with tamoxifen therapy

Uterine serous carcinoma (USC) is the prototype of type II endometrial cancer. Endometrial intraepithelial carcinoma (EIC) is the precursor lesion of USC, Rarely, USC and EIC may arise within and be largely confined to otherwise benign endometrial polyps. This report describes 5 such cases. The patients ranged in age from 67 to 89 years, with a mean age of 75 years. In 2 of the cases there was a history of tamoxifen therapy. In 2 cases USC or EIC was confined to the endometrial polyp, and in 3 cases there was focal involvement of nonpolypoid endometrium. In 1 case there was a single small focus of extrauterine tumor within an ovarian vascular channel. In 2 cases the invasive tumor within the polyp also contained areas of endometrioid adenocarcinoma, and in 2 cases there was a component of clear cell carcinoma. In all cases USC and EIC were strongly reactive for p53 and showed a high proliferation index with MIB1. Two cases were negative with estrogen receptor, and 3 cases exhibited positive staining. The cases reported herein show that USC and EIC may rarely arise in benign endometrial polyps and that extrauterine involvement may be present without myometrial infiltration. Because 2 of the patients had been taking tamoxifen, this raises the possibility of an association between tamoxifen and the development of USC and EIC in the endometrial polyps that are characteristic of this medication.     

HAX-1 is overexpressed in hepatocellular carcinoma and promotes cell proliferation

Hepatocellular carcinoma (HCC) is the most common primary liver tumor. Due to the asymptomatic nature of early HCC and lack of effective screening strategies, 80% of patients present with advanced HCC at the time of diagnosis. Novel molecular marker identification will be valuable for effective diagnosis and treatment. In this study we reported HCLS1-associated protein X-1 (HAX-1) is overexpression in HCC in human HCC sample. Furthermore, we provided evidence that HAX-1 expression positively correlated with that of Ki67 in patient sample. Statistic analysis indicated that HAX-1 expression level significantly correlated with clinic outcome of HCC. Cell based assay revealed that knockdown of HAX-1 inhibits cell proliferation. This result suggests that HAX-1 can be a novel molecular marker for HCC.     

p53 immunohistochemistry is an accurate surrogate for TP53 mutational analysis in endometrial carcinoma biopsies

TP53 mutations are considered a surrogate biomarker of the serous-like ‘copy number high’ molecular subtype of endometrial carcinoma (EC). In ovarian carcinoma, p53 immunohistochemistry (IHC) accurately reflects mutational status with almost 100% specificity but its performance in EC has not been established. This study tested whether p53 IHC reliably predicts TP53 mutations identified by next-generation sequencing (NGS) in EC biopsy samples for all ECs and as part of a molecular classification algorithm after exclusion of cases harbouring mismatch repair defects (MMRd) or pathogenic DNA polymerase epsilon exonuclease domain mutations (POLEmut). A secondary aim assessed inter-laboratory variability in p53 IHC. From a total of 207 cases from five centres (37–49 cases per centre), p53 IHC carried out at a central reference laboratory was compared with local IHC (n = 164) and curated tagged-amplicon NGS TP53 sequencing results (n = 177). Following consensus review, local and central p53 IHC results were concordant in 156/164 (95.1%) tumours. Discordant results were attributable to both interpretive and technical differences in staining between the local and central laboratories. When results were considered as any mutant pattern versus wild-type pattern staining, however, there was disagreement between local and central review in only one case. The concordance between p53 IHC and TP53 mutation was 155/168 (92.3%) overall, and 117/123 (95.1%) after excluding MMRd and POLEmut EC. Three (3/6) discordant results were in serous carcinomas with complete absence of p53 staining but no detectable TP53 mutation. Subclonal mutant p53 IHC expression was observed in 9/177 (5.1%) cases, of which four were either MMRd or POLEmut. Mutant pattern p53 IHC was observed in 63/63 (100%) serous carcinomas that were MMR-proficient/POLE exonuclease domain wild-type. Optimised p53 IHC performs well as a surrogate test for TP53 mutation in EC biopsies, demonstrates excellent inter-laboratory reproducibility, and has high clinical utility for molecular classification algorithms in EC. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.