Adjuvant Treatment for POLE Proofreading Domain-Mutant Cancers: Sensitivity to Radiotherapy, Chemotherapy, and Nucleoside Analogues

High prevalence of "non-pathogenic" POLE mutation with poor prognosis in a cohort of endometrial cancer from South India

OBJECTIVE

The Cancer Genome Atlas (TCGA) project identified favorable prognosis regarding the ultra-mutated endometrial cancer (EC) subtype linked to polymerase epsilon gene (POLE) mutations. This study investigated POLE mutations in EC of Indian patients.

METHODS

This retrospective analytical study was conducted between January 2016 and January 2023 at the Government Medical College, Kozhikode, and the MVR Cancer Center, Kozhikode, Kerala. Sanger sequencing of POLE gene exons 9 and 13 in 151 EC patients was carried out to analyze the relationship between mutations and epidemiological factors, clinicopathologic features, and treatment outcomes.

RESULTS

Among 151 cases enrolled, 39 were unique POLE-mutated cases. Significant associations were high-grade tumors, myometrial invasion >50%, and Lymph-vascular space invasion (LVSI). The median follow-up was 40 months (95% confidence interval [CI], 34-46). A lower mean disease-specific survival (DSS) of 51.7 months (95% CI, 43.7-59.6) was noted in the POLE-mutated group compared with 72.11 months (95% CI, 67.60-76.62) for the POLE wild-type. A statistically significant hazard ratio (HR) of 2.683 for DSS in the POLE-mutated group was noted. In advanced stages (FIGO stages II-IV), a nine-fold HR for DSS and overall survival (OS) compared with POLE wild-type was identified. After controlling for treatment effects using Cox proportional HR, advanced-stage POLE-mutated tumors had a significantly higher HR of 8.67 for DSS compared with POLE-wild-type tumors of the same stage.

CONCLUSION

This study identified a unique set of POLE mutations in Indian EC patients associated with poor prognosis, which were particularly pronounced in advanced stages. Advanced stage of presentation, type of POLE mutations, and possibly ethnicity are predictors of adverse outcomes in POLE-mutated EC. The present study highlights ethnicity as a determinant of phenotypic expression of genetic change.

[Endometrial carcinoma: molecular classification in routine pathology]

The molecular classification of endometrial carcinoma defines four main groups: polymerase‑ɛ(PolE) gene mutated, microsatellite unstable (MSI), p53 abnormal tumors and tumors with no specific molecular profile (NSMP). This classification provides significant insights into the prognosis and therapeutic decisions. Each group exhibits unique genetic profiles identified through immunohistochemistry and molecular diagnostics, enabling personalized treatment. The identification of these molecular signatures necessitates precise analytical methods, selected based on the local circumstances at each site. The approach to molecular classification highlights the critical role of pathology in the diagnosis and emphasizes the necessity of collaboration between the clinic and pathology.

Unsolved Issues in the Integrated Histo-Molecular Classification of Endometrial Carcinoma and Therapeutic Implications

Endometrial carcinoma (EC) is the most frequent gynecological cancer, with an increasing incidence and mortality in recent times. The last decade has represented a true revolution with the development of the integrated histo-molecular classification of EC, which allows for the stratification of patients with morphologically indistinguishable disease into groups with different prognoses. Particularly, the POLE-mutated subgroup exhibits outstanding survival. Nevertheless, the indiscriminate application of molecular classification appears premature. Its prognostic significance has been proven mainly in endometrioid EC, the most common histotype, but it has yet to be convincingly confirmed in the other minor histotypes, which indeed account for a relevant proportion of EC mortality. Moreover, its daily use both requires a mindful pathologist who is able to correctly evaluate and unambiguously report immunohistochemical staining used as a surrogated diagnostic tool and is hampered by the unavailability of POLE mutation analysis. Further molecular characterization of ECs is needed to allow for the identification of better-tailored therapies in different settings, as well as the safe avoidance of surgery for fertility preservation. Hopefully, the numerous ongoing clinical trials in the adjuvant and metastatic settings of EC will likely produce evidence to refine the histo-molecular classification and therapeutic guidelines. Our review aims to retrace the origin and evolution of the molecular classification for EC, reveal its strengths and limitations, show clinical relevance, and uncover the desired future developments.

Molecular Classification of Endometrial Cancer and Its Impact on Therapy Selection

Endometrial cancer (EC) accounts for 90% of uterine cancer cases. It is considered not only one of the most common gynecological malignancies but also one of the most frequent cancers among women overall. Nowadays, the differentiation of EC subtypes is based on immunohistochemistry and molecular techniques. It is considered that patients' prognosis and the implementation of the appropriate treatment depend on the cancer subtype. Patients with pathogenic variants in POLE have the most favorable outcome, while those with abnormal p53 protein have the poorest. Therefore, in patients with POLE mutation, the de-escalation of postoperative treatment may be considered, and patients with abnormal p53 protein should be subjected to intensive adjuvant therapy. Patients with a DNA mismatch repair (dMMR) deficiency are classified in the intermediate prognosis group as EC patients without a specific molecular profile. Immunotherapy has been recognized as an effective treatment method in patients with advanced or recurrent EC with a mismatch deficiency. Thus, different adjuvant therapy approaches, including targeted therapy and immunotherapy, are being proposed depending on the EC subtype, and international guidelines, such as those published by ESMO and ESGO/ESTRO/ESP, include recommendations for performing the molecular classification of all EC cases. The decision about adjuvant therapy selection has to be based not only on clinical data and histological type and stage of cancer, but, following international recommendations, has to include EC molecular subtyping. This review describes how molecular classification could support more optimal therapeutic management in endometrial cancer patients.

Efficacy of fertility-sparing treatment with LNG-IUS is associated with different ProMisE subtypes of endometrial carcinoma or atypical endometrial hyperplasia

OBJECTIVE

To determine whether proactive molecular risk classifier for endometrial cancer (ProMisE) could be used to assess the prognosis of patients with atypical endometrial hyperplasia (AEH) or early-stage endometrial cancer (EC) treated with levonorgestrel-releasing intrauterine system (LNG-IUS).

METHODS

A retrospective cohort study was conducted among 93 AEH or early-stage EC patients who received LNG-IUS to preserve fertility . By immunohistochemistry and gene sequencing, 4 subtypes of ProMisE were identified (p53 wild type [p53 wt], mismatch repair-deficient [MMRd], p53-abnormal, and POLE-mutated). The primary outcome was the time to complete response (CR) after LNG-IUS therapy. Secondary outcomes included the recurrence rate after CR and success rate of conception.

RESULTS

Among the 93 patients, 15 (16.1%) were classified as MMRd, 6 (6.5%) as POLE-mutated, 5 (5.4%) as p53-abnormal, and 67 (72.0%) as p53 wt. Comparison of serum cancer antigen 125, family history of tumor, and positive rates of programmed cell death 1 ligand 1 protein and Ki67 protein in 4 groups showed statistically significant differences (p<0.05). Patients with the p53-abnormal subtype had the lowest overall CR rate (40%) and the highest recurrence rate (2/2). Patients with POLE-mutated subtype had the best prognosis, and all 6 patients achieved CR. When patients achieved complete remission, assisted reproductive technology was more likely to help them conceive than natural conception (p<0.05).

CONCLUSION

Patients with early-stage EC or AEH who are more likely to benefit from fertility-sparing treatment can be identified using ProMisE classifier. Patients with POLE-mutated are suitable for fertility-sparing treatment with LNG-IUS.

Differentiation of survival outcomes by anatomic involvement and histology with the revised 2023 International Federation of Gynecology and Obstetrics staging system for endometrial cancer

OBJECTIVES

The International Federation of Gynecology and Obstetrics (FIGO) staging system for endometrial cancer underwent revision in 2023, incorporating histology, lymphovascular space invasion, and molecular classification. Herein, we compare overall survival (OS) outcomes by anatomic and histologic involvement for patients staged by the 2009 system versus 2023 system.

METHODS

The National Cancer Database (NCDB) was queried for patients with newly-diagnosed uterine adenocarcinoma from 2004 to 2015, with follow-up data extending through 2020. Stage was determined by both the 2009 and 2023 FIGO staging systems. Kaplan-Meier estimators and Cox proportional hazards models were used for survival analysis.

RESULTS

A total of 134,677 patients were analyzed. Per 2023 classification, patients with stage I disease decreased from 96,161 to 70,101 (-27.1%, p < 0.01), while stage II disease increased from 9295 to 36,294 (+390.5%, p < 0.01). Greatest OS change was observed for 2023 stage IA3 patients (low-risk, synchronous endometrial and ovarian tumors with a clonal relationship), whose 10-year OS was 73.4%, compared to 52.6% for 2009 stage IIIA disease. Ten-year OS for 2023 stage IIIB2 (pelvic peritoneal involvement), previously 2009 stage IVB, was 49.4%, compared to 18.7% for 2009 stage IVB patients. Akaike information criterion, Bayesian information criterion, and Harrel's concordance index were used to evaluate OS prognostication of each staging system across all stages, with likelihood ratio favoring the 2023 system (p = 0.020).

CONCLUSIONS

With FIGO's 2023 endometrial cancer anatomic and histologic staging system, stage migration is greatest in early-stage disease. New staging groups may offer more precise prognostication. These changes may affect future management.

Predictive and prognostic biomarkers in female genital tract tumours: an update highlighting their clinical relevance and practical issues

The evaluation of biomarkers by molecular techniques and immunohistochemistry has become increasingly relevant to the treatment of female genital tract tumours as a consequence of the greater availability of therapeutic options and updated disease classifications. For ovarian cancer, mutation testing for BRCA1/2 is the standard predictive biomarker for poly(ADP-ribose) polymerase inhibitor therapy, while homologous recombination deficiency testing may allow the identification of eligible patients among cases without demonstrable BRCA1/2 mutations. Clinical recommendations are available which specify how these predictive biomarkers should be applied. Mismatch repair (MMR) protein and folate receptor alpha immunohistochemistry may also be used to guide treatment in ovarian cancer. In endometrial cancer, MMR immunohistochemistry is the preferred test for predicting benefit from immune checkpoint inhibitor (ICI) therapy, but molecular testing for microsatellite instability may have a supplementary role. HER2 testing by immunohistochemistry and in situ hybridisation is applicable to endometrial serous carcinomas to assess trastuzumab eligibility. Immunohistochemistry for oestrogen receptor and progesterone receptor expression may be used for prognostication in endometrial cancer, but its predictive value for hormonal therapy is not yet proven. POLE mutation testing and p53 immunohistochemistry (as a surrogate for TP53 mutation status) serve as prognostic markers for favourable and adverse outcomes, respectively, in endometrial cancer, especially when combined with MMR testing for molecular subtype designation. For cervical cancer, programmed death ligand 1 immunohistochemistry may be used to predict benefit from ICI therapy although its predictive value is under debate. In vulvar cancer, p16 and p53 immunohistochemistry has established prognostic value, stratifying patients into three groups based on the human papillomavirus and TP53 mutation status of the tumour. Awareness of the variety and pitfalls of expression patterns for p16 and p53 in vulvar carcinomas is crucial for accurate designation. It is hoped that collaborative efforts in standardising and optimising biomarker testing for gynaecological tumours will contribute to evidence-based therapeutic decisions.

Molecular subtypes of endometrial cancer: Implications for adjuvant treatment strategies

BACKGROUND

When determining adjuvant treatment for endometrial cancer, the decision typically relies on factors such as cancer stage, histologic grade, subtype, and a few histopathologic markers. The Cancer Genome Atlas revealed molecular subtyping of endometrial cancer, which can provide more accurate prognostic information and guide personalized treatment plans.

OBJECTIVE

To summarize the expression and molecular basis of the main biomarkers of endometrial cancer.

SEARCH STRATEGY

PubMed was searched from January 2000 to March 2023.

SELECTION CRITERIA

Studies evaluating molecular subtypes of endometrial cancer and implications for adjuvant treatment strategies.

DATA COLLECTION AND ANALYSIS

Three authors independently performed a comprehensive literature search, collected and extracted data, and assessed the methodological quality of the included studies.

MAIN RESULTS

We summarized the molecular subtyping of endometrial cancer, including mismatch repair deficient, high microsatellite instability, polymerase epsilon (POLE) exonuclease domain mutated, TP53 gene mutation, and non-specific molecular spectrum. We also summarized planned and ongoing clinical trials and common therapy methods in endometrial cancer. POLE mutated endometrial cancer consistently exhibits favorable patient outcomes, regardless of adjuvant therapy. Genomic similarities between p53 abnormality endometrial cancer and high-grade serous ovarian cancer suggested possible overlapping treatment strategies. High levels of immune checkpoint molecules, such as programmed cell death 1 and programmed cell death 1 ligand 1 can counterbalance mismatch repair deficient endometrial cancer immune phenotype. Hormonal treatment is an appealing option for high-risk non-specific molecular spectrum endometrial cancers, which are typically endometrioid and hormone receptor positive. Combining clinical and pathologic characteristics to guide treatment decisions for patients, including concurrent radiochemotherapy, chemotherapy, inhibitor therapy, endocrine therapy, and immunotherapy, might improve the management of endometrial cancer and provide more effective treatment options for patients.

CONCLUSIONS

We have characterized the molecular subtypes of endometrial cancer and discuss their value in terms of a patient-tailored therapy in order to prevent significant under- or overtreatment.

The Significance of International Federation of Gynecology and Obstetrics Grading in Microsatellite Instability-High and POLE-Mutant Endometrioid Endometrial Carcinoma

With the advancement of diagnostic molecular technology and the molecular classification of endometrial endometrioid carcinoma (EEC), it remains to be seen whether conventional International Federation of Gynecology and Obstetrics (FIGO) grading retains clinical significance in certain molecular subtypes of EECs. In this study, we explored the clinical significance of FIGO grading in microsatellite instability-high (MSI-H) and POLE-mutant EECs. A total of 162 cases of MSI-H EECs and 50 cases of POLE-mutant EECs were included in the analysis. Significant differences in tumor mutation burden (TMB), progression-free survival, and disease-specific survival were seen between the MSI-H and POLE-mutant cohorts. Within the MSI-H cohort, there were statistically significant differences in TMB and stage at presentation across FIGO grades, but not survival. Within the POLE-mutant cohort, there was significantly greater TMB with increasing FIGO grade, but there were no significant differences in stage or survival. In both the MSI-H and POLE-mutant cohorts, log-rank survival analysis showed no statistically significant difference in progression-free and disease-specific survival across FIGO grades. Similar findings were also seen when a binary grading system was utilized. Since FIGO grade was not associated with survival, we conclude that the intrinsic biology of these tumors, characterized by their molecular profile, may override the significance of FIGO grading.

Replication DNA polymerases, genome instability and cancer therapies

It has been over a decade since the initial identification of exonuclease domain mutations in the genes encoding the catalytic subunits of replication DNA polymerases ϵ and δ (POLE and POLD1) in tumors from highly mutated endometrial and colorectal cancers. Interest in studying POLE and POLD1 has increased significantly since then. Prior to those landmark cancer genome sequencing studies, it was well documented that mutations in replication DNA polymerases that reduced their DNA synthesis accuracy, their exonuclease activity or their interactions with other factors could lead to increased mutagenesis, DNA damage and even tumorigenesis in mice. There are several recent, well-written reviews of replication DNA polymerases. The aim of this review is to gather and review in some detail recent studies of DNA polymerases ϵ and δ as they pertain to genome instability, cancer and potential therapeutic treatments. The focus here is primarily on recent informative studies on the significance of mutations in genes encoding their catalytic subunits (POLE and POLD1), mutational signatures, mutations in associated genes, model organisms, and the utility of chemotherapy and immune checkpoint inhibition in polymerase mutant tumors.

FIGO staging of endometrial cancer: 2023

INTRODUCTION

Many advances in the understanding of the pathologic and molecular features of endometrial cancer have occurred since the FIGO staging was last updated in 2009. Substantially more outcome and biological behavior data are now available regarding the several histological types. Molecular and genetic findings have accelerated since the publication of The Cancer Genome Atlas (TCGA) data and provide improved clarity on the diverse biological nature of this collection of endometrial cancers and their differing prognostic outcomes. The goals of the new staging system are to better define these prognostic groups and create substages that indicate more appropriate surgical, radiation, and systemic therapies.

METHODS

The FIGO Women's Cancer Committee appointed a Subcommittee on Endometrial Cancer Staging in October 2021, represented by the authors. Since then, the committee members have met frequently and reviewed new and established evidence on the treatment, prognosis, and survival of endometrial cancer. Based on these data, opportunities for improvements in the categorization and stratification of these factors were identified in each of the four stages. Data and analyses from the molecular and histological classifications performed and published in the recently developed ESGO/ESTRO/ESP guidelines were used as a template for adding the new subclassifications to the proposed molecular and histological staging system.

RESULTS

Based on the existing evidence, the substages were defined as follows: Stage I (IA1): non-aggressive histological type of endometrial carcinoma limited to a polyp or confined to the endometrium; (IA2) non-aggressive histological types of endometrium involving less than 50% of the myometrium with no or focal lymphovascular space invasion (LVSI) as defined by WHO criteria; (IA3) low-grade endometrioid carcinomas limited to the uterus with simultaneous low-grade endometrioid ovarian involvement; (IB) non-aggressive histological types involving 50% or more of the myometrium with no LVSI or focal LVSI; (IC) aggressive histological types, i.e. serous, high-grade endometrioid, clear cell, carcinosarcomas, undifferentiated, mixed, and other unusual types without any myometrial invasion. Stage II (IIA): non-aggressive histological types that infiltrate the cervical stroma; (IIB) non-aggressive histological types that have substantial LVSI; or (IIC) aggressive histological types with any myometrial invasion. Stage III (IIIA): differentiating between adnexal versus uterine serosa infiltration; (IIIB) infiltration of vagina/parametria and pelvic peritoneal metastasis; and (IIIC) refinements for lymph node metastasis to pelvic and para-aortic lymph nodes, including micrometastasis and macrometastasis. Stage IV (IVA): locally advanced disease infiltrating the bladder or rectal mucosa; (IVB) extrapelvic peritoneal metastasis; and (IVC) distant metastasis. The performance of complete molecular classification (POLEmut, MMRd, NSMP, p53abn) is encouraged in all endometrial cancers. If the molecular subtype is known, this is recorded in the FIGO stage by the addition of "m" for molecular classification, and a subscript indicating the specific molecular subtype. When molecular classification reveals p53abn or POLEmut status in Stages I and II, this results in upstaging or downstaging of the disease (IICmp53abn or IAmPOLEmut).

SUMMARY

The updated 2023 staging of endometrial cancer includes the various histological types, tumor patterns, and molecular classification to better reflect the improved understanding of the complex nature of the several types of endometrial carcinoma and their underlying biologic behavior. The changes incorporated in the 2023 staging system should provide a more evidence-based context for treatment recommendations and for the more refined future collection of outcome and survival data.

FIGO staging of endometrial cancer: 2023

INTRODUCTION

Many advances in the understanding of the pathologic and molecular features of endometrial cancer have occurred since the FIGO staging was last updated in 2009. Substantially more outcome and biological behavior data are now available regarding the several histological types. Molecular and genetic findings have accelerated since the publication of The Cancer Genome Atlas (TCGA) data and provide improved clarity on the diverse biological nature of this collection of endometrial cancers and their differing prognostic outcomes. The goals of the new staging system are to better define these prognostic groups and create substages that indicate more appropriate surgical, radiation, and systemic therapies.

METHODS

The FIGO Women's Cancer Committee appointed a Subcommittee on Endometrial Cancer Staging in October 2021, represented by the authors. Since then, the committee members have met frequently and reviewed new and established evidence on the treatment, prognosis, and survival of endometrial cancer. Based on these data, opportunities for improvements in the categorization and stratification of these factors were identified in each of the four stages. Data and analyses from the molecular and histological classifications performed and published in the recently developed ESGO/ESTRO/ESP guidelines were used as a template for adding the new subclassifications to the proposed molecular and histological staging system.

RESULTS

Based on the existing evidence, the substages were defined as follows: Stage I (IA1): non-aggressive histological type of endometrial carcinoma limited to a polyp or confined to the endometrium; (IA2) non-aggressive histological types of endometrium involving less than 50% of the myometrium with no or focal lymphovascular space invasion (LVSI) as defined by WHO criteria; (IA3) low-grade endometrioid carcinomas limited to the uterus with simultaneous low-grade endometrioid ovarian involvement; (IB) non-aggressive histological types involving 50% or more of the myometrium with no LVSI or focal LVSI; (IC) aggressive histological types, i.e. serous, high-grade endometrioid, clear cell, carcinosarcomas, undifferentiated, mixed, and other unusual types without any myometrial invasion. Stage II (IIA): non-aggressive histological types that infiltrate the cervical stroma; (IIB) non-aggressive histological types that have substantial LVSI; or (IIC) aggressive histological types with any myometrial invasion. Stage III (IIIA): differentiating between adnexal versus uterine serosa infiltration; (IIIB) infiltration of vagina/parametria and pelvic peritoneal metastasis; and (IIIC) refinements for lymph node metastasis to pelvic and para-aortic lymph nodes, including micrometastasis and macrometastasis. Stage IV (IVA): locally advanced disease infiltrating the bladder or rectal mucosa; (IVB) extrapelvic peritoneal metastasis; and (IVC) distant metastasis. The performance of complete molecular classification (POLEmut, MMRd, NSMP, p53abn) is encouraged in all endometrial cancers. If the molecular subtype is known, this is recorded in the FIGO stage by the addition of "m" for molecular classification, and a subscript indicating the specific molecular subtype. When molecular classification reveals p53abn or POLEmut status in Stages I and II, this results in upstaging or downstaging of the disease (IICmp53abn or IAmPOLEmut ).

SUMMARY

The updated 2023 staging of endometrial cancer includes the various histological types, tumor patterns, and molecular classification to better reflect the improved understanding of the complex nature of the several types of endometrial carcinoma and their underlying biologic behavior. The changes incorporated in the 2023 staging system should provide a more evidence-based context for treatment recommendations and for the more refined future collection of outcome and survival data.

Refining adjuvant treatment in endometrial cancer based on molecular features: the RAINBO clinical trial program

BACKGROUND

The endometrial cancer molecular classification has been integrated into the 2020 World Health Organization (WHO) diagnostic classification and European treatment guidelines, and provides direction towards more effective and less toxic adjuvant treatment strategies for women with endometrial cancer.

PRIMARY OBJECTIVES

The RAINBO program of clinical trials will investigate four molecular class-directed adjuvant treatment strategies following surgical resection to either increase cure rates through the addition of novel targeted therapies or safely reduce toxicity and improve quality of life through treatment de-escalation.

STUDY HYPOTHESIS

Molecular-directed adjuvant treatment strategies will improve clinical outcomes and reduce toxicity of unwarranted therapies in women with endometrial cancer. The overarching and translational research RAINBO program will advance knowledge of predictive and prognostic (bio)markers that will improve prognostication and treatment allocation.

TRIAL DESIGN

The RAINBO program is a platform of four international clinical trials and an overarching research program. The randomized phase III p53abn-RED trial for women with invasive stage I-III p53abn endometrial cancer compares adjuvant chemoradiation followed by olaparib for 2 years with adjuvant chemoradiation alone. The randomized phase III MMRd-GREEN trial for women with stage II (with lymphovascular space invasion (LVSI)) or stage III mismatch repair-deficient (MMRd) endometrial cancer compares adjuvant radiotherapy with concurrent and adjuvant durvalumab for 1 year to radiotherapy alone. The randomized phase III NSMP-ORANGE trial is a treatment de-escalation trial for women with estrogen receptor positive stage II (with LVSI) or stage III no specific molecular profile (NSMP) endometrial cancer comparing radiotherapy followed by progestin for 2 years to adjuvant chemoradiation. The POLEmut-BLUE trial is a phase II trial in which the safety of de-escalation of adjuvant therapy is investigated for women with stage I-III POLEmut endometrial cancer: no adjuvant therapy for lower-risk disease and no adjuvant therapy or radiotherapy alone for higher-risk disease. The overarching RAINBO program will combine data and tumor material of all participants to perform translational research and evaluate molecular class-based adjuvant therapy in terms of efficacy, toxicity, quality of life, and cost-utility.

MAJOR INCLUSION/EXCLUSION CRITERIA

Inclusion criteria include a histologically confirmed diagnosis of endometrial cancer treated by hysterectomy and bilateral salpingo-oophorectomy with or without lymphadenectomy or sentinel lymph node biopsy, with no macroscopic residual disease after surgery and no distant metastases, and molecular classification according to the WHO 2020 algorithm.

PRIMARY ENDPOINTS

Recurrence-free survival at 3 years in the p53abn-RED, MMRd-GREEN, and NSMP-ORANGE trials and pelvic recurrence at 3 years in the POLEmut-BLUE trial.

SAMPLE SIZE

The p53abn-RED trial will include 554 patients, the MMRd-GREEN trial 316, the NSMP-ORANGE trial 600, and the POLEmut-BLUE trial 145 (120 for lower-risk disease and approximately 25 for higher-risk disease). The overarching research program will pool the four sub-trials resulting in a total sample size of around 1600.

ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS

The four clinical trials will have different completion dates; main results are expected from 2028.

TRIAL REGISTRATION NUMBER

The RAINBO program is registered at clinicaltrials.gov (NCT05255653).

Characterization of hotspot exonuclease domain mutations in the DNA polymerase ϵ gene in endometrial cancer

Objective

This study was aimed to profile hotspot exonuclease domain mutations (EDMs) of the DNA polymerase ϵ gene (POLE) in endometrial cancer (EC) and to investigate the effects of EDMs on tumor cell behavior and catalytic activities of Polϵ.

Methods

POLE sequencing was performed in tumor tissue samples from patients with EC to identify hotspot EDMs. Bioinformatics tools were used to select the potential pathogenic EDMs. The association of EDMs with the clinical outcomes of patients was assessed. EC cells were transfected with wildtype POLE or POLE variants to examine the effects of the EDMs on EC cell behavior, including cell cycle, migration, and invasion. Co-immunoprecipitation was employed to obtain FLAG-tagged wildtype and mutant catalytic subunits of Polϵ, followed by the assessment of polymerase and exonuclease activities.

Results

In addition to previously reported P286R and V411L, R375Q and P452L were identified as novel, and deleterious POLE hotspot EDMs of EC. Patients in EDM group had significantly better clinical outcomes than the rest of the cohort. Compared with wildtype POLE, overexpression of POLE variants promoted cisplatin resistance, G0/G1 cell cycle arrest, and cell migration and invasion in EC cells. Overexpression of POLE variants significantly increased the abundance of 3’-OH and upregulated the expression of DNA mismatch repair genes in HEK293T cells. Compared with wildtype Polϵ, Pol ϵ mutants exhibited undermined polymerase and exonuclease abilities in the presence of mismatched nucleotides in HEK293 cells.

Conclusion

We characterized the of hotspot exonuclease domain mutations in the DNA polymerase ϵ gene and identified P286R, V411L, R375Q, and P452L as pathogenic POLE hotspot EDMs in endometrial cancer. These hotspot EDMs are associated with the malignant behavior of endometrial cancer cells in vitro and favorable prognosis in patients, suggesting that POLE affects a wide range of cellular processes beyond DNA replication and proofreading.

Effects of Tumor Mutational Burden and Gene Alterations Associated with Radiation Response on Outcomes of Postoperative Radiation Therapy in Non-Small Cell Lung Cancer

PURPOSE

Postoperative radiation therapy (PORT) in resected non-small cell lung cancer (NSCLC) improves locoregional outcomes, but recent randomized data do not support its unselected use. We assessed if tumor mutational burden (TMB) and mutations in genes associated with radiation sensitivity can select patients for PORT.

METHODS AND MATERIALS

Patients with resected NSCLC treated with and without PORT who underwent tumor genomic profiling were examined. The incidence of locoregional failures (LRFs) in patients with deleterious mutations in DNA damage response and repair (DDR) genes and genes associated with radiation resistance (KEAP1/NFE2L2/STK11/PIK3CA) were investigated. Cox modeling and receiver operating characteristic curve (ROC) analysis assessed the relationship between TMB and locoregional control (LRC).

RESULTS

Eighty-nine patients with NSCLC treated with PORT were analyzed, with a 2-year LRF rate of 19% (95% confidence interval, 10%-27%). Among patients treated with PORT, those with mutations in radiation resistance genes (n = 16 [18%]) had significantly more LRFs than patients without mutations (2-year LRF rate: 60% vs 11%; P < .001). On multivariate analysis, radiation-resistance mutations were associated with LRF after PORT (hazard ratio, 7.42; P < .001). Patients with mutations identified in DDR genes (n = 15 [17%]) had significantly improved LRC (P = .048) and no LRF events after PORT. On multivariate analysis, a higher TMB was associated with improved LRC after PORT (hazard ratio, 0.86; P = .01), and TMB was associated with PORT outcomes (area under ROC curve, 0.67-0.77). These genomic markers were not similarly associated with LRF in patients not treated with PORT.

CONCLUSIONS

The data suggest that patients with radiation-resistance gene alterations may derive minimal benefit from PORT, whereas patients with high TMB and/or alterations in DDR genes may benefit from PORT and be suited for future precision-RT strategies. Prospective studies are necessary to validate these findings.

Polymerase Epsilon-Associated Ultramutagenesis in Cancer

With advances in next generation sequencing (NGS) technologies, efforts have been made to develop personalized medicine, targeting the specific genetic makeup of an individual. Somatic or germline DNA Polymerase epsilon (PolE) mutations cause ultramutated (>100 mutations/Mb) cancer. In contrast to mismatch repair-deficient hypermutated (>10 mutations/Mb) cancer, PolE-associated cancer is primarily microsatellite stable (MSS) In this article, we provide a comprehensive review of this PolE-associated ultramutated tumor. We describe its molecular characteristics, including the mutation sites and mutation signature of this type of tumor and the mechanism of its ultramutagenesis. We discuss its good clinical prognosis and elucidate the mechanism for enhanced immunogenicity with a high tumor mutation burden, increased neoantigen load, and enriched tumor-infiltrating lymphocytes. We also provide the rationale for immune checkpoint inhibitors in PolE-mutated tumors.

Follicular Helper T-Cell-Based Classification of Endometrial Cancer Promotes Precise Checkpoint Immunotherapy and Provides Prognostic Stratification

Despite the fact that management of EC is moving towards four TCGA-based molecular classifications, a pronounced variation in immune response among these molecular subtypes limits its clinical use. We aimed to investigate the determinant biomarker of ICI response in endometrial cancer (EC). We characterized transcriptome signatures associated with tumor immune microenvironment in EC. Two immune infiltration signatures were identified from the TCGA database (n = 520). The high- and low-infiltration clusters were compared for differences in patient clinical characteristics, genomic features, and immune cell transcription signatures for ICI prediction. A Lasso Cox regression model was applied to construct a prognostic gene signature. Time-dependent receiver operating characteristic curve, Kaplan-Meier curve, nomogram, and decision curve analyses were used to assess the prediction capacity. The efficacy of potential biomarker was validated by the Karolinska endometrial cancer cohort (n = 260). Immune signature profiling suggested that T follicular helper-like cells (Tfh) may be an important and favorable factor for EC; high Tfh infiltration showed potential for clinical use in the anti-PD-1 treatment. A Tfh Infiltration Risk Model (TIRM) established using eight genes was validated, and it outperformed the Immune Infiltration Risk Model. The TIRM had a stable prognostic value in combination with clinical risk factors and could be considered as a valuable tool in a clinical prediction model. We identified CRABP1 as an individual poor prognostic factor in EC. The Tfh-based classification distinguishes immune characteristics and predicts ICI efficacy. A nomogram based on Tfh-related risk score accurately predicted the prognosis of patients with EC, demonstrating superior performance to TCGA-based classification.

Clinicopathological and molecular characterization of high-grade endometrial carcinoma with POLE mutation: a single center study

Objective

The molecular classification system of endometrial carcinoma (EC) in ‘The Cancer Genome Atlas’ is widely acknowledged for its prognostic utility. Subsequently, more simplified classification system that incorporate DNA polymerase epsilon (POLE) exonuclease domain mutations, mismatch repair deficiencies (MMRd), and abnormal p53 (P53abn) has also demonstrated its clinical utility. These classifications helped identifying a ‘POLE ultramutated’ (POLEmut) category of patients, most of whom show excellent prognoses despite having high-grade ECs. We aimed to investigate the clinicopathological and molecular characteristics of high-grade ECs with POLEmut.

Methods

We investigated 414 patients with high-grade ECs (including endometrioid carcinomas grade 3, serous carcinomas, clear cell carcinomas, mixed carcinomas, undifferentiated and dedifferentiated carcinomas, and carcinosarcomas) by sequencing and immunohistochemical staining.

Results

Forty-three tumors (10.4%) were classified as POLEmut, including 2 with new, possibly pathogenic POLE mutations at P286C and L424V. These patients had very good prognoses except for 1 with stage IV disease and residual tumor. Eleven patients in this group also had P53abn and 4 had MMRd; molecular analysis revealed that patients with synchronous POLE pathogenic mutation and other mutations had a POLEmut or MMRd phenotype; survival analysis found no difference in prognosis between these patient categories. The prognoses of patients in the POLEmut EC group were not significantly influenced by treatment or risk category.

Conclusions

Patients with high-grade EC exhibiting POLEmut have very good clinical outcomes, and should be identified urgently in daily work owing to their conflicting morphology. Our findings also provide guidance on subclassifying ECs with poor histological appearance.

We investigated patients with high-grade endometrial carcinoma (EC) exhibiting POLEmut. We identified 2 new POLE mutations that are possibly pathogenic. All our 43 patients except for the one with stage IV disease had good prognoses. The prognoses of patients with POLEmut EC were not significantly influenced by treatment or risk level.

Induction of mismatch repair deficiency, compromised DNA damage signaling and compound hypermutagenesis by a dietary mutagen in a cell-based model for Lynch Syndrome

The prevalent cancer predisposition Lynch syndrome (LS, OMIM #120435) is caused by an inherited heterozygous defect in any of the four core DNA mismatch repair (MMR) genes MSH2, MSH6, MLH1 or PMS2. MMR repairs errors by the replicative DNA polymerases in all proliferating tissues. Its deficiency, following somatic loss of the wild type copy, results in a spontaneous mutator phenotype that underlies the rapid development of, predominantly, colorectal cancer (CRC) in LS. Here we have addressed the hypothesis that aberrant responses of intestinal stem cells to diet-derived mutagens may be causally involved in the restricted cancer tropism of LS. To test this we have generated a panel of isogenic mouse embryonic stem (mES) cells with heterozygous or homozygous disruption of multiple MMR genes and investigated their responses to the common dietary mutagen and carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Our data reveal that PhIP can inactivate the wild type allele of heterozygous mES cells via the induction of either loss of heterozygosity (LOH) or intragenic mutations. Moreover, while protective DNA damage signaling (DDS) is compromised, PhIP induces more mutations in Msh2, Mlh1, Msh6 or Pms2-deficient mES cells than in wild type cells. Combined with their spontaneous mutator phenotypes, this results in a compound hypermutator phenotype. Together, these results indicate that dietary mutagens may promote CRC development in LS at multiple levels, providing a rationale for dietary modifications in the management of LS.

Radical hysterectomy versus simple hysterectomy and brachytherapy for stage II endometrial cancer

PURPOSE

To compare the survival outcome between radical hysterectomy and simple hysterectomy with radiation therapy in patients with stage II endometrial cancer.

MATERIALS AND METHODS

This is a retrospective cohort study based on the SEER database from January 1, 1988 to December 31, 2015.

RESULTS

Of 577 patients were enrolled in the study, 117 patients received radical hysterectomy and 460 patients received simple hysterectomy combined with vaginal brachytherapy. All patients received external beam radiation therapy after the surgery. The median follow-up duration was 82.77 ± 1.44 months. No differences were found on the baseline information between two groups. Both the 5-year overall survival (62.31% vs. 78.48%, p < 0.001) and 5-year cause-specific survival (74.60 vs. 85.38%, p = 0.01) were shorter in radical hysterectomy than in simple hysterectomy combined with vaginal brachytherapy group. However, the positive outcomes were further validated in patients with high-risk endometrial cancer, not in patients with grade 1-2 low-risk endometrial cancer both on cause-specific survival and overall survival. In patients with grade 3 low-risk endometrial cancer, the tendency was only found with lower overall survival not cause-specific survival.

CONCLUSIONS

This study revealed that in patients' high-risk stage II endometrial cancer, radical hysterectomy was associated with shorter survival outcome than simple hysterectomy combined with vaginal brachytherapy.

The emerging role of molecular pathology in directing the systemic treatment of endometrial cancer

Following the discovery of the four molecular subtypes of endometrial cancer (EC) by The Cancer Genome Atlas (TCGA) in 2013, subsequent studies used surrogate markers to develop and validate a clinically relevant EC classification tool to recapitulate TCGA subtypes. Molecular classification combines focused sequencing (POLE) and immunohistochemistry (mismatch repair and p53 proteins) to assign patients with EC to one of four molecular subtypes: POLEmut, MMRd, p53abn and NSMP (no specific molecular profile). Unlike histopathological evaluation, the molecular subtyping of EC offers an objective and reproducible classification system that has been shown to have prognostic value and therapeutic implications. It is an exciting time in EC care where we have moved beyond treatment based on histomorphology alone, and molecular classification will now finally allow assessment of treatment efficacy within biologically similar tumours. It is now recommended that molecular classification should be considered for all ECs, and should be performed routinely in all high grade tumours. It is also recommended to incorporate molecular classification into standard pathology reporting and treatment decision-making algorithms. In this review, we will discuss how the molecular classification of EC can be used to guide both conventional and targeted therapy in this new molecular era.

Endometrial Cancer Molecular Characterization: The Key to Identifying High-Risk Patients and Defining Guidelines for Clinical Decision-Making?

Endometrial carcinomas (EC) are the sixth most common cancer in women worldwide and the most prevalent in the developed world. ECs have been historically sub-classified in two major groups, type I and type II, based primarily on histopathological characteristics. Notwithstanding the usefulness of such classification in the clinics, until now it failed to adequately stratify patients preoperatively into low- or high-risk groups. Pieces of evidence point to the fact that molecular features could also serve as a base for better patients' risk stratification and treatment decision-making. The Cancer Genome Atlas (TCGA), back in 2013, redefined EC into four main molecular subgroups. Despite the high hopes that welcomed the possibility to incorporate molecular features into practice, currently they have not been systematically applied in the clinics. Here, we outline how the emerging molecular patterns can be used as prognostic factors together with tumor histopathology and grade, and how they can help to identify high-risk EC subpopulations for better risk stratification and treatment strategy improvement. Considering the importance of the use of preclinical models in translational research, we also discuss how the new patient-derived models can help in identifying novel potential targets and help in treatment decisions.

Evaluation of treatment effects in patients with endometrial cancer and POLE mutations: An individual patient data meta-analysis

BACKGROUND

Endometrial cancers (ECs) with somatic mutations in DNA polymerase epsilon (POLE) are characterized by unfavorable pathological features, which prompt adjuvant treatment. Paradoxically, women with POLE-mutated EC have outstanding clinical outcomes, and this raises concerns of overtreatment. The authors investigated whether favorable outcomes were independent of treatment.

METHODS

A PubMed search for POLE and endometrial was restricted to articles published between March 1, 2012, and March 1, 2018, that provided individual patient data (IPD), adjuvant treatment, and survival. Following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) reporting guidelines for IPD, the authors used univariate and multivariate one-stage meta-analyses with mixed effects Cox models (random effects for study cohorts) to infer the associations of treatment, traditional prognostic factors, and outcome, which was defined as the time from first diagnosis to any adverse event (progression/recurrence or death from EC).

RESULTS

Three hundred fifty-nine women with POLE-mutated EC were identified; 294 (82%) had pathogenic mutations. Worse outcomes were demonstrated in patients with nonpathogenic POLE mutations (hazard ratio, 3.42; 95% confidence interval, 1.47-7.58; log-rank P < .01). Except for stage (P < .01), traditional prognosticators were not associated with progression/recurrence or death from disease. Adverse events were rare (11 progressions/recurrences and 3 disease-specific deaths). Salvage rates in patients who experienced recurrence were high and sustained, with 8 of 11 alive without evidence of disease (range, 5.5-14.2 years). Adjuvant treatment was not associated with outcome.

CONCLUSIONS

Clinical outcomes for ECs with pathogenic POLE mutations are not associated with most traditional risk parameters, and patients do not appear to benefit from adjuvant therapy. The observed low rates of recurrence/progression and the high and sustained salvage rates raise the possibility of safely de-escalating treatment for these patients.

LAY SUMMARY

Ten percent of all endometrial cancers have mutations in the DNA repair gene DNA polymerase epsilon (POLE). Women who have endometrial cancers with true POLE mutations experience almost no recurrences or deaths from their cancer even when their tumors appear to have very unfavorable characteristics. Additional therapy (radiation and chemotherapy) does not appear to improve outcomes for women with POLE-mutated endometrial cancer, and this supports the move to less therapy and less associated toxicity. Diligent classification of endometrial cancers by molecular features provides valuable information to inform prognosis and to direct treatment/no treatment.

Impact of Molecular Classification on Treatment Paradigms in Uterine Cancers

PURPOSE OF REVIEW

This article will discuss the recent data on the prognostic significance of molecular classification of endometrial carcinoma, as well as its impact on directing treatment decisions.

RECENT FINDINGS

Molecular classification has emerged as a complement to the current paradigm of endometrial cancer (EC) risk stratification. POLE mutations appear to portend favorable prognoses, but data are insufficient to indicate withholding treatment based on this signature. Copy number high (CNH) EC carries a worse prognosis and may benefit from more aggressive therapy. MMRd tumors are likely to have other prognostic features that indicate adjuvant treatment and many recurrences respond favorably to pembrolizumab. Progression of molecular profiling may allow further discrimination of the no specific molecular profile (NSMP) group. Treatment for this group remains largely based on conventional risk factors. For both the NSMP and the CNH groups, treatment with lenvatinib and pembrolizumab is an attractive contemporary option for recurrence management. Molecular classification is a useful adjunct to conventional risk stratification paradigms for both prognostic counseling and treatment selection. Clinical trials incorporating molecular signatures in assigning treatment strategies may further elucidate the value of this classification system.

POLE and Mismatch Repair Status, Checkpoint Proteins and Tumor-Infiltrating Lymphocytes in Combination, and Tumor Differentiation: Identify Endometrial Cancers for Immunotherapy

OBJECTIVE

Although Polymerase-epsilon (POLE)-mutated and mismatch repair (MMR)-deficient endometrial cancers (ECs) are considered as promising candidates for anti-PD-1/PD-L1 therapy, selecting only these patients may exclude other patients who could potentially respond to this treatment strategy, highlighting the need of additional biomarkers for better patient selection. This study aims to evaluate potential predictive biomarkers for anti-PD-1/PD-L1 therapy in addition to POLE mutation (POLEm) and MMR deficiency (MMRd).

METHODS

We performed next generation sequencing for POLE from 202 ECs, and immunohistochemistry for MLH1, MSH2, MSH6, PMS2, CD3, CD8, PD-1 and PD-L1 on full-section slides from these ECs. We assessed the association of POLEm and MMRd with clinicopathologic features, expression of check point proteins, and density of tumor-infiltrating lymphocytes (TILs). Prognostic impact of these immune markers was also evaluated.

RESULTS

POLEm, MMRd and high-grade tumors exhibited elevated level of TILs. Increased expression of PD-1 and PD-L1 was observed in MMRd and high-grade ECs. A subgroup of MMR proficient ECs also harbored increased density of TILs, and positive expression of PD-1 and PD-L1. In addition, negative expression of checkpoint proteins and high density of TILs in combination was associated with good prognosis.

CONCLUSIONS

Candidates for PD-1 blockade may extend beyond POLEm and MMRd ECs, additional factors such as tumor grade, and combination of TILs levels and expression of checkpoint proteins may need to be considered for better patient selection.

Molecular subtype diagnosis of endometrial carcinoma: comparison of the next-generation sequencing panel and Proactive Molecular Risk Classifier for Endometrial Cancer classifier

The Cancer Genome Atlas-based molecular classification of endometrial carcinoma (EC) has the potential to better identify those patients whose disease is likely to behave differently than predicted when using traditional risk stratification; however, the optimal approach to molecular subtype assignment in routine practice remains undetermined. The aim of this study was to compare the results of two different widely available approaches to diagnosis the EC molecular subtype. EC specimens from 60 patients were molecularly subclassified using two different methods, by using the FoundationOne CDx next-generation sequencing (NGS) panel and using the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) classifier and performing immunostaining for mismatch repair proteins and p53. POLE mutation status was derived from FoundationOne results in both settings. Molecular classification based on ProMisE was successful for all 60 tumors. Microsatellite instability status could be determined based on the NGS panel results in 53 of 60 tumors, so ProMisE and NGS molecular subtype assignment could be directly compared for these 53 tumors. Molecular subtype diagnosis based on NGS and ProMisE was in agreement for 52 of 53 tumors. One tumor was microsatellite stable but showed loss of MLH1 and PMS2 expression. Molecular subtype diagnosis of EC based on the NGS panel of formalin-fixed paraffin-embedded ECs and based primarily on immunostaining (ProMisE) yields identical results in 98.1% (52/53, kappa = 0.97) of cases. Although results obtained using these two approaches are comparable, each has advantages and disadvantages that will influence the choice of the method to be used in clinical practice.

Risk Reclassification of Patients with Endometrial Cancer Based on Tumor Molecular Profiling: First Real World Data

Recently, guidelines for endometrial cancer (EC) were released that guide treatment decisions according to the tumors' molecular profiles. To date, no real-world data regarding the clinical feasibility of molecular profiling have been released. This retrospective, monocentric study investigated the clinical feasibility of molecular profiling and its potential impact on treatment decisions. Tumor specimens underwent molecular profiling (testing for genetic alterations, (immune-)histological examination of lymphovascular space invasion (LVSI), and L1CAM) as part of the clinical routine and were classified according to the European Society for Medical Oncology (ESMO) classification system and to an integrated molecular risk stratification. Shifts between risk groups and potential treatment alterations are described. A total of 60 cases were included, of which twelve were excluded (20%), and eight of the remaining 48 were not characterized (drop-out rate of 16.7%). Molecular profiling revealed 4, 6, 25, and 5 patients with DNA polymerase-epsilon mutation, microsatellite instability, no specific molecular profile, and TP53 mutation, respectively. Three patients had substantial LVSI, and four patients showed high L1CAM expression. Molecular profiling took a median of 18.5 days. Substantial shifts occurred between the classification systems: four patients were upstaged, and 19 patients were downstaged. Molecular profiling of EC specimens is feasible in a daily routine, and new risk classification systems will change treatment decisions substantially.

Novel Antibiotics Targeting Bacterial Replicative DNA Polymerases

Multidrug resistance is a worldwide problem that is an increasing threat to global health. Therefore, the development of new antibiotics that inhibit novel targets is of great urgency. Some of the most successful antibiotics inhibit RNA transcription, RNA translation, and DNA replication. Transcription and translation are inhibited by directly targeting the RNA polymerase or ribosome, respectively. DNA replication, in contrast, is inhibited indirectly through targeting of DNA gyrases, and there are currently no antibiotics that inhibit DNA replication by directly targeting the replisome. This contrasts with antiviral therapies where the viral replicases are extensively targeted. In the last two decades there has been a steady increase in the number of compounds that target the bacterial replisome. In particular a variety of inhibitors of the bacterial replicative polymerases PolC and DnaE have been described, with one of the DNA polymerase inhibitors entering clinical trials for the first time. In this review we will discuss past and current work on inhibition of DNA replication, and the potential of bacterial DNA polymerase inhibitors in particular as attractive targets for a new generation of antibiotics.

A Modern Approach to Endometrial Carcinoma: Will Molecular Classification Improve Precision Medicine in the Future?

Endometrial cancer has been histologically classified as either an estrogen-dependent cancer with a favorable outcome or an estrogen-independent cancer with a worse prognosis. These parameters, along with the clinical attributions, have been the basis for risk stratification. Recent molecular and histopathological findings have suggested a more complex approach to risk stratification. Findings from the Cancer Genome Atlas Research Network established four distinctive genomic groups: ultramutated, hypermutated, copy-number low and copy-number high prognostic subtypes. Subsequently, more molecular and histopathologic classifiers were evaluated for their prognostic and predictive value. The impact of molecular classification is evident and will be recognized by the upcoming WHO classification. Further research is needed to give rise to a new era of molecular-based endometrial carcinoma patient care.

Incorporation of molecular characteristics into endometrial cancer management

Histopathological evaluation including subtyping and grading is the current cornerstone for endometrial cancer (EC) classification. This provides clinicians with prognostic information and input for further treatment recommendations. Nonetheless, patients with histologically similar ECs may have very different outcomes, notably in patients with high‐grade endometrial carcinomas. For endometrial cancer, four molecular subgroups have undergone extensive studies in recent years: POLE ultramutated (POLEmut), mismatch repair‐deficient (MMRd), p53 mutant (p53abn) and those EC lacking any of these alterations, referred to as NSMP (non‐specific molecular profile). Several large studies confirm the prognostic relevance of these molecular subgroups. However, this ‘histomolecular’ approach has so far not been implemented in clinical routine. The ongoing PORTEC4a trial is the first clinical setting in which the added value of integrating molecular parameters in adjuvant treatment decisions will be determined. For diagnostics, the incorporation of the molecular parameters in EC classification will add a level of objectivity which will yield biologically more homogeneous subclasses. Here we illustrate how the management of individual EC patients may be impacted when applying the molecular EC classification. We describe our current approach to the integrated diagnoses of EC with a focus on scenarios with conflicting morphological and molecular findings. We also address several pitfalls accompanying the diagnostic implementation of molecular EC classification and give practical suggestions for diagnostic scenarios.

Molecular Classification of the PORTEC-3 Trial for High-Risk Endometrial Cancer: Impact on Prognosis and Benefit From Adjuvant Therapy

PURPOSE

The randomized Adjuvant Chemoradiotherapy Versus Radiotherapy Alone in Women With High-Risk Endometrial Cancer (PORTEC-3) trial investigated the benefit of combined adjuvant chemotherapy and radiotherapy (CTRT) versus radiotherapy alone (RT) for women with high-risk endometrial cancer (EC). Because The Cancer Genome Atlas defined an EC molecular classification with strong prognostic value, we investigated prognosis and impact of chemotherapy for each molecular subgroup using tissue samples from PORTEC-3 trial participants.

METHODS

Paraffin-embedded tissues of 423 consenting patients were collected. Immunohistochemistry for p53 and mismatch repair (MMR) proteins, and DNA sequencing for POLE exonuclease domain were done to classify tumors as p53 abnormal (p53abn), POLE-ultramutated (POLEmut), MMR-deficient (MMRd), or no specific molecular profile (NSMP). The primary end point was recurrence-free survival (RFS). Kaplan-Meier method, log-rank test, and Cox model were used for analysis.

RESULTS

Molecular analysis was successful in 410 high-risk EC (97%), identifying the 4 subgroups: p53abn EC (n = 93; 23%), POLEmut (n = 51; 12%), MMRd (n = 137; 33%), and NSMP (n = 129; 32%). Five-year RFS was 48% for patients with p53abn EC, 98% for POLEmut EC, 72% for MMRd EC, and 74% for NSMP EC (P < .001). The 5-year RFS with CTRT versus RT for p53abn EC was 59% versus 36% (P = .019); 100% versus 97% for patients with POLEmut EC (P = .637); 68% versus 76% (P = .428) for MMRd EC; and 80% versus 68% (P = .243) for NSMP EC.

CONCLUSION

Molecular classification has strong prognostic value in high-risk EC, with significantly improved RFS with adjuvant CTRT for p53abn tumors, regardless of histologic type. Patients with POLEmut EC had an excellent RFS in both trial arms. EC molecular classification should be incorporated in the risk stratification of these patients as well as in future trials to target specific subgroups of patients.

POLE Mutation Characteristics in a Chinese Cohort with Endometrial Carcinoma

Objective

To study the characteristics of polymerase epsilon (POLE) exonuclease domain mutations in Chinese patients with endometrial carcinoma (EC).

Methods

This study analyzed data from 529 patients with EC in The Cancer Genome Atlas (TCGA) and 467 EC patients evaluated at the Shanghai First Maternity and Infant Hospital (SFMIH). POLE mutation heterogeneity was analyzed in paired curettage and hysterectomy samples from 120 SFMIH patients. Sanger sequencing identified mutations in the POLE exonuclease domain, and correlations between POLE mutation status and various clinicopathological features were determined by chi-squared testing and Cohen’s kappa analysis, with Kaplan–Meier survival curves generated to assess correlations between POLE mutation status and overall survival (OS).

Results

Thirty-five mutations were identified in 467 samples (7.5%), and novel mutations were detected in the SFMIH cohort. Compared to the TCGA cohort, the SFMIH cohort had fewer POLE mutations when matched by age (<60) and histology (endometrioid) (p < 0.001 and p = 0.010, respectively). In our study cohort, POLE mutations were significantly associated with adjuvant treatment (p = 0.029), and patients with POLE mutations who underwent chemoradiotherapy had a poor OS (p < 0.0001). Notably, shorter OS was significantly associated with POLE mutations in hysterectomy samples from patients aged >60 years or with stage I disease in the paired curettage-hysterectomy group.

Conclusion

The significant difference in POLE mutation profiles between the TCGA and SFMIH cohorts, as well as the poor consistency between the curettage and hysterectomy samples, suggests that different parameters need to be applied to determine the prognosis of patients with EC in China.

Adjuvant treatment of endometrial cancer in molecular era: Are we ready to move on?

For many decades, the Bokhman dualist vision was used to stratify endometrial cancer (EC) in good or bad tumors. Nowadays, a more robust and reliable molecular stratification is taking place with the The Cancer Genome Atlas Research Network (TCGA) classification bringing new and important information in the field. Collaborative groups are replicating TCGA using accessible tools with immunohistochemistry. It's time to move on and include this information along with pathology features to better delineate adjuvant treatment in EC.

High polymerase ε expression associated with increased CD8+T cells improves survival in patients with non-small cell lung cancer

DNA replicase polymerase ε (POLE) is critical in proofreading and correcting errors of DNA replication. Low POLE expression plays a pivotal role in accumulation of mutations and onset of cancer, contributing to development and growth of tumor cells. The aim of this study is to reveal the survival, alternative genes and antitumoral immune activities in non-small cell lung cancer (NSCLC) patients with low POLE expression and provide treatment strategies that can increase their survival rates. This study investigated the clinicopathologic parameters, various tumor-infiltrating lymphocytes (TILs), endogenous retrovirus, molecular interactions and in vitro drug screen according to POLE mutation/expression in 168 and 1,019 NSCLC patients from the Konkuk University Medical Center (KUMC) and the Cancer Genome Atlas, respectively. We identified mutations of 75 genes in the sequencing panels, with POLE frame shift p.V1446fs being the most frequent (56.8%) in KUMC based on 170 targeted sequencing panels. Mutant and high expression of POLE correlated with favorable prognosis with increased TILs and tumor mutation burden, compared with wild type and low expression of POLE. We found specific molecular interactions associated with cell cycle and antigen presentation. An in vitro drug screen identified dasatinib that inhibited growth of the NSCLC cell line with low POLE expression. POLE could contribute to the future development of anticancer drugs for patients with NSCLC.

The brave new world of endometrial cancer : Future implications for adjuvant treatment decisions

PURPOSE

For many decades, endometrial cancer (EC) has been considered as a homogenous tumor entity with good prognosis. The currently valid risk stratification considers clinical and pathological factors. Treatment recommendations differ considerably from country to country.

MATERIALS AND METHODS

The Cancer Genome Atlas (TCGA) Research Network has shown that ECs should be reclassified into four novel molecular prognostic groups, with the potential of changing adjuvant management of EC patients: ultra-mutated, hyper-mutated, copy-number low, and copy-number high. Clinical examples are shown, and the available literature has been highlighted. The European Society of Gynaecological Oncology (ESGO) guideline for endometrial cancer takes the new classification system into consideration for adjuvant treatment decisions and will be published this year.

RESULTS

In the near future, we expect new treatment recommendations that may differ considerably from the clinicopathologically driven recommendations on the basis of our deeper insight and better understanding of molecular markers in endometrial cancer. The PORTEC 4a study is the only recruiting study which randomizes patients to adjuvant or no adjuvant treatment on the basis of the aforementioned new classification system.

CONCLUSION

The aim of the new classification is a more personalized adjuvant radio(chemo)therapy decision and better oncologic outcomes or avoidance of overtreatment.

Improving response to progestin treatment of low-grade endometrial cancer

OBJECTIVES

This review examines how response rates to progestin treatment of low-grade endometrial cancer can be improved. In addition to providing a brief overview of the pathogenesis of low-grade endometrial cancer, we discuss limitations in the current classification of endometrial cancer and how stratification may be refined using molecular markers to reproducibly identify 'low-risk' cancers which may represent the best candidates for progestin therapy. We also discuss constraints in current approaches to progestin treatment of low-grade endometrial cancer and perform a systematic review of predictive biomarkers.

METHODS

PubMed, ClinicalTrials.gov, and Cochrane Library were searched for studies reporting pre-treatment biomarkers associated with outcome in women with low-grade endometrial cancer or endometrial hyperplasia with an intact uterus who received progestin treatment. Studies of fewer than 50 women were excluded. The study protocol was registered in PROSPERO (ID 152374). A descriptive synthesis of pre-treatment predictive biomarkers reported in the included studies was conducted.

RESULTS

Of 1908 records reviewed, 19 studies were included. Clinical features such as age or body mass index cannot predict progestin response. Lesions defined as 'low-risk' by FIGO criteria (stage 1A, grade 1) can respond well; however, the reproducibility and prognostic ability of the current histopathological classification system is suboptimal. Molecular markers can be reproducibly assessed, have been validated as prognostic biomarkers, and may inform patient selection for progestin treatment. DNA polymerase epsilon (POLE)-ultramutated tumors and a subset of p53 wild-type or DNA mismatch repair (MMR)-deficient tumors with 'low-risk' features (eg, progesterone and estrogen receptor-positive) may have improved response rates, though this needs to be validated.

DISCUSSION

Molecular markers can identify cases which may be candidates for progestin treatment. More work is needed to validate these biomarkers and potentially identify new ones. Predictive biomarkers are anticipated to inform future research into progestin treatment of low-grade endometrial cancer and ultimately improve patient outcomes.

Clinicopathological and molecular characterisation of 'multiple-classifier' endometrial carcinomas

Endometrial carcinoma (EC) molecular classification based on four molecular subclasses identified in The Cancer Genome Atlas (TCGA) has gained relevance in recent years due to its prognostic utility and potential to predict benefit from adjuvant treatment. While most ECs can be classified based on a single classifier (POLE exonuclease domain mutations - POLEmut, MMR deficiency - MMRd, p53 abnormal - p53abn), a small but clinically relevant group of tumours harbour more than one molecular classifying feature and are referred to as 'multiple-classifier' ECs. We aimed to describe the clinicopathological and molecular features of multiple-classifier ECs with abnormal p53 (p53abn). Within a cohort of 3518 molecularly profiled ECs, 107 (3%) tumours displayed p53abn in addition to another classifier(s), including 64 with MMRd (MMRd-p53abn), 31 with POLEmut (POLEmut-p53abn), and 12 with all three aberrations (MMRd-POLEmut-p53abn). MMRd-p53abn ECs and POLEmut-p53abn ECs were mostly grade 3 endometrioid ECs, early stage, and frequently showed morphological features characteristic of MMRd or POLEmut ECs. 18/28 (60%) MMRd-p53abn ECs and 7/15 (46.7%) POLEmut-p53abn ECs showed subclonal p53 overexpression, suggesting that TP53 mutation was a secondary event acquired during tumour progression. Hierarchical clustering of TCGA ECs by single nucleotide variant (SNV) type and somatic copy number alterations (SCNAs) revealed that MMRd-p53abn tumours mostly clustered with single-classifier MMRd tumours (20/23) rather than single-classifier p53abn tumours (3/23), while POLEmut-p53abn tumours mostly clustered with single-classifier POLEmut tumours (12/13) and seldom with single-classifier p53abn tumours (1/13) (both p ≤ 0.001, chi-squared test). Finally, the clinical outcome of patients with MMRd-p53abn and POLEmut-p53abn ECs [stage I 5-year recurrence-free survival (RFS) of 92.2% and 94.1%, respectively] was significantly different from single-classifier p53abn EC (stage I RFS 70.8%, p = 0.024 and p = 0.050, respectively). Our results support the classification of MMRd-p53abn EC as MMRd and POLEmut-p53abn EC as POLEmut. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Germline POLE and POLD1 proofreading domain mutations in endometrial carcinoma from Middle Eastern region

Background

Endometrial carcinoma (EC) accounts for 5.8% of all cancers in Saudi females. Although most ECs are sporadic, 2–5% tend to be familial, being associated with Lynch syndrome and Cowden syndrome. In this study, we attempted to uncover the frequency, spectrum and phenotype of germline mutations in the proofreading domain of POLE and POLD1 genes in a large cohort of ECs from Middle Eastern region.

Methods

We performed Capture sequencing and Sanger sequencing to screen for proofreading domains of POLE and POLD1 genes in 432 EC cases, followed by evaluation of protein expression using immunohistochemistry. Variant interpretation was performed using PolyPhen-2, MutationAssessor, SIFT, CADD and Mutation Taster.

Results

In our cohort, four mutations (0.93%) were identified in 432 EC cases, two each in POLE and POLD1 proofreading domains. Furthermore, low expression of POLE and POLD1 was noted in 41.1% (170/1414) and 59.9% (251/419) of cases, respectively. Both the cases harboring POLE mutation showed high nuclear expression of POLE protein, whereas, of the two POLD1 mutant cases, one case showed high expression and another case showed low expression of POLD1 protein.

Conclusions

Our study shows that germline mutations in POLE and POLD1 proofreading region are a rare cause of EC in Middle Eastern population. However, it is still feasible to screen multiple cancer related genes in EC patients from Middle Eastern region using multigene panels including POLE and POLD1.

Clinical actionability of molecular targets in endometrial cancer

Endometrial cancer accounts for ~76,000 deaths among women each year worldwide. Disease mortality and the increasing number of new diagnoses make endometrial cancer an important consideration in women's health, particularly in industrialized countries, where the incidence of this tumour type is highest. Most endometrial cancers are carcinomas, with the remainder being sarcomas. Endometrial carcinomas can be classified into several histological subtypes, including endometrioid, serous and clear cell carcinomas. Histological subtyping is currently used routinely to guide prognosis and treatment decisions for endometrial cancer patients, while ongoing studies are evaluating the potential clinical utility of molecular subtyping. In this Review, we summarize the overarching molecular features of endometrial cancers and highlight recent studies assessing the potential clinical utility of specific molecular features for early detection, disease risk stratification and directing targeted therapies.

Selecting Adjuvant Treatment for Endometrial Carcinoma Using Molecular Risk Factors

PURPOSE OF REVIEW

To provide an overview of common molecular risk factors in endometrial cancer (EC) with the possibility to improve adjuvant treatment selection.

RECENT FINDINGS

Recent studies have discovered and confirmed four different molecular subclasses in EC, with each having a distinct prognosis; POLE-ultramutated, microsatellite unstable, copy-number low, and copy-number high. Subsequent studies have shown that combining both molecular with clinicopathological risk factors can potentially improve adjuvant treatment selection for women with high-intermediate risk EC. For high risk and advanced stage EC, several molecular alterations are being explored for targeted therapy. Molecular alterations are frequently found in endometrial cancer and have currently not been implemented in the treatment guidelines for EC. Assessment of molecular alterations can distinguish patients that require less or more intensified adjuvant treatment. Trials investigating targeted therapies in EC are ongoing and have shown some promising results, however, more evidence is needed and results of randomized trials have to be awaited.

Approaches to functionally validate candidate genetic variants involved in colorectal cancer predisposition

Most next generation sequencing (NGS) studies identified candidate genetic variants predisposing to colorectal cancer (CRC) but do not tackle its functional interpretation to unequivocally recognize a new hereditary CRC gene. Besides, germline variants in already established hereditary CRC-predisposing genes or somatic variants share the same need when trying to categorize those with relevant significance. Functional genomics approaches have an important role in identifying the causal links between genetic architecture and phenotypes, in order to decipher cellular function in health and disease. Therefore, functional interpretation of identified genetic variants by NGS platforms is now essential. Available approaches nowadays include bioinformatics, cell and molecular biology and animal models. Recent advances, such as the CRISPR-Cas9, ZFN and TALEN systems, have been already used as a powerful tool with this objective. However, the use of cell lines is of limited value due to the CRC heterogeneity and its close interaction with microenvironment. Access to tridimensional cultures or organoids and xenograft models that mimic the in vivo tissue architecture could revolutionize functional analysis. This review will focus on the application of state-of-the-art functional studies to better tackle new genes involved in germline predisposition to this neoplasm.

POLE proofreading defects: Contributions to mutagenesis and cancer

DNA polymerases are uniquely poised to contribute to the elevated mutation burdens seen in many human tumors. These mutations can arise through a number of different polymerase-dependent mechanisms, including intrinsic errors made using template DNA and precursor dNTPs free from chemical modifications, misinsertion events opposite chemically damaged template DNA or insertion events using modified nucleotides. While specific DNA repair polymerases have been known to contribute to tumorigenesis, the role of replication polymerases in mutagenesis in human disease has come into sharp focus over the last decade. This review describes how mutations in these replication DNA polymerases help to drive mutagenesis and tumor development, with particular attention to DNA polymerase epsilon. Recent studies using cancer genome sequencing, mutational signature analyses, yeast and mouse models, and the influence of mismatch repair on tumors with DNA polymerase mutations are discussed.

Analysis of mutational signatures in primary and metastatic endometrial cancer reveals distinct patterns of DNA repair defects and shifts during tumor progression

OBJECTIVE

Mutational signatures provide insights into the biological processes shaping tumor genomes and may inform patient therapy. We sought to define the mutational signatures of i) endometrioid and serous endometrial carcinomas (ECs), stratified into the four molecular subtypes, ii) uterine carcinosarcomas, and iii) matched primary and metastatic ECs.

METHODS

Whole-exome sequencing MC3 data from primary endometrioid and serous carcinomas (n = 232) and uterine carcinosarcomas (n = 57) from The Cancer Genome Atlas (TCGA), and matched primary and metastatic ECs (n = 61, 26 patients) were reanalyzed, subjected to mutational signature analysis using deconstructSigs, and correlated with clinicopathologic and genomic data.

RESULTS

POLE (ultramutated) and MSI (hypermutated) molecular subtypes displayed dominant mutational signatures associated with POLE mutations (15/17 cases) and microsatellite instability (55/65 cases), respectively. Most endometrioid and serous carcinomas of copy-number low (endometrioid) and copy-number high (serous-like) molecular subtypes, and carcinosarcomas displayed a dominant aging-associated signature 1. Only 15% (9/60) of copy-number high (serous-like) ECs had a dominant signature 3 (homologous recombination DNA repair deficiency (HRD)-related), a prevalence significantly lower than that found in high-grade serous ovarian carcinomas (54%, p < 0.001) or basal-like breast cancers (46%, p < 0.001). Shifts from aging- or POLE- to MSI-related mutational processes were observed in the progression from primary to metastatic ECs in a subset of cases.

CONCLUSIONS

The mutational processes underpinning ECs vary even among tumors of the same TCGA molecular subtype and in the progression from primary to metastatic ECs. Only a minority of copy-number high (serous-like) ECs display genomics features of HRD and would likely benefit from HRD-directed therapies.