Microcystic, elongated, and fragmented pattern invasion is mainly associated with isolated tumor cell pattern metastases in International Federation of Gynecology and Obstetrics grade I endometrioid endometrial cancer

Molecular Classification of Endometrial Endometrioid Carcinoma With Microcystic Elongated and Fragmented Pattern

The studies on the molecular classification of endometrioid carcinoma (EC) with microcystic, elongated, and fragmented (MELF) pattern invasion are limited. In this study, 77 cases of ECs with MELF patterns in Chinese women were collected. The molecular classification of the fifth edition of the World Health Organization was used to classify the molecular subtypes using immunohistochemistry staining (mismatch repair [MMR]-immunohistochemistry: MSH2, MSH6, MLH1, and PMS2; p53) and Sanger sequencing targeted POLE . The results showed that the prevalence of the 4 molecular subtypes in EC with MELF pattern was 6.5% (5/77) for POLE mutation, 20.8% (16/77) for MMR deficient, 11.7% (9/77) for p53-mutant, and 61.0% (47/77) for no specific molecular profile. The clinicopathological characteristics of each subtype were compared. The p53-mutant and no specific molecular profile subgroups were associated with higher International Federation of Gynecology and Obstetrics stage and International Federation of Gynecology and Obstetrics grade, deeper myometrial invasion, lymphovascular space invasion, lymph node metastasis, and absence of tumor-infiltrating lymphocytes, whereas the POLE mutation and MMR deficient subgroups were associated with lower aggressive features and prominent tumor-infiltrating lymphocytes. Progression-free survival showed that the p53-mutant and no specific molecular profile subgroups had a poorer prognosis than the POLE mutation and MMR deficient subgroups. However, lymph node metastasis was an independent factor associated with a higher risk of disease recurrence in multivariate analysis. In conclusion, ECs with MELF patterns can be divided into 4 molecular subtypes with discrepancies in aggressive clinicopathological characteristics and tumor-infiltrating lymphocytes. Molecular classification has clinical significance in a morpho-molecular approach for ECs with MELF patterns.

Radiation Therapy for Endometrial Cancer: An American Society for Radiation Oncology Clinical Practice Guideline

PURPOSE

With the results of several recently published clinical trials, this guideline informs on the use of adjuvant radiation therapy (RT) and systemic therapy in the treatment of endometrial cancer. Updated evidence-based recommendations provide indications for adjuvant RT and the associated techniques, the utilization and sequencing of adjuvant systemic therapies, and the effect of surgical staging techniques and molecular tumor profiling.

METHODS

The American Society for Radiation Oncology convened a multidisciplinary task force to address 6 key questions that focused on the adjuvant management of patients with endometrial cancer. The key questions emphasized the (1) indications for adjuvant RT, (2) RT techniques, target volumes, dose fractionation, and treatment planning aims, (3) indications for systemic therapy, (4) sequencing of systemic therapy with RT, (5) effect of lymph node assessment on utilization of adjuvant therapy, and (6) effect of molecular tumor profiling on utilization of adjuvant therapy. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for quality of evidence grading and strength of recommendation.

RESULTS

The task force recommends RT (either vaginal brachytherapy or external beam RT) be given based on the patient's clinical-pathologic risk factors to reduce risk of vaginal and/or pelvic recurrence. When external beam RT is delivered, intensity modulated RT with daily image guided RT is recommended to reduce acute and late toxicity. Chemotherapy is recommended for patients with International Federation of Gynecology and Obstetrics (FIGO) stage I to II with high-risk histologies and those with FIGO stage III to IVA with any histology. When sequencing chemotherapy and RT, there is no prospective data to support an optimal sequence. Sentinel lymph node mapping is recommended over pelvic lymphadenectomy for surgical nodal staging. Data on sentinel lymph node pathologic ultrastaging status supports that patients with isolated tumor cells be treated as node negative and adjuvant therapy based on uterine risk factors and patients with micrometastases be treated as node positive. The available data on molecular characterization of endometrial cancer are compelling and should be increasingly considered when making recommendations for adjuvant therapy.

CONCLUSIONS

These recommendations guide evidence-based best clinical practices on the use of adjuvant therapy for endometrial cancer.

Data Set for the Reporting of Endometrial Cancer: Recommendations From the International Collaboration on Cancer Reporting (ICCR)

Endometrial cancer is one of the most common cancers among women. The International Collaboration on Cancer Reporting (ICCR) developed a standardized endometrial cancer data set in 2011, which provided detailed recommendations for the reporting of resection specimens of these neoplasms. A new data set has been developed, which incorporates the updated 2020 World Health Organization Classification of Female Genital Tumors, the Cancer Genome Atlas (TCGA) molecular classification of endometrial cancers, and other major advances in endometrial cancer reporting, all of which necessitated a major revision of the data set. This updated data set has been produced by a panel of expert pathologists and an expert clinician and has been subject to international open consultation. The data set includes core elements which are unanimously agreed upon as essential for cancer diagnosis, clinical management, staging, or prognosis and noncore elements which are clinically important, but not essential. Explanatory notes are provided for each element. Adoption of this updated data set will result in improvements in endometrial cancer patient care.

The Role of Immunohistochemistry Markers in Endometrial Cancer with Mismatch Repair Deficiency: A Systematic Review

The objective of this systematic review was to summarize our current knowledge of the role of immunohistochemistry (IHC) markers for identifying mismatch repair-deficient (MMRd) tumors in endometrial cancer (EC). Identification of MMRd tumors, which occur in 13% to 30% of all ECs, has become critical for patients with colorectal and endometrial cancer for therapeutic management, clinical decision making, and prognosis. This review was conducted by two authors applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the following terms: “immunohistochemistry and microsatellite instability endometrial cancer” or “immunohistochemistry and mismatch repair endometrial cancer” or “immunohistochemistry and mismatch repair deficient endometrial cancer”. Among 596 retrieved studies, 161 fulfilled the inclusion criteria. Articles were classified and presented according to their interest for the diagnosis, prognosis, and theragnostics for patients with MMRd EC. We identified 10, 18, and 96 articles using IHC expression of two, three, or four proteins of the MMR system (MLH1, MSH2, MHS6, and PMS2), respectively. MLH1 promoter methylation was analyzed in 57 articles. Thirty-four articles classified MMRd tumors with IHC markers according to their prognosis in terms of recurrence-free survival (RFS), overall survival (OS), stage, grade, and lymph node invasion. Theragnostics were studied in eight articles underlying the important concentration of PD-L1 in MMRd EC. Even though the role of IHC has been challenged, it represents the most common, robust, and cheapest method for diagnosing MMRd tumors in EC and is a valuable tool for exploring novel biotherapies and treatment modalities.

Clinicopathologic association and prognostic impact of microcystic, elongated and fragmented pattern invasion, combined with tumor budding in endometrioid endometrial cancer

AIM

As a special invasive pattern seen in low-grade endometrial carcinoma, microcystic, elongated and fragmented (MELF) pattern is related to lymph node metastasis. Tumor budding (TB) is another histological marker in many cancers associated with tumor aggressiveness. Herein, we evaluated the impact of MELF pattern combined with TB about clinicopathological features and prognosis in endometrioid endometrial cancer (EEC). To verify the relationship between the two morphological markers and microsatellite status in EEC, the primary mismatch repair (MMR) proteins were detected by immunohistochemistry.

METHODS

One hundred and seventy-two cases of ECC diagnosed between 2011 and 2016 were reviewed with a median follow up of 47.5 months. MELF pattern and TB were examined on all H&E-stained slides. Primary MMR proteins (MLH1, MSH2, MSH6, and PMS2) were also detected.

RESULTS

Based on MELF pattern and TB, 172 patients were divided into the following four groups: MELF(-)/TB(+) (n = 41), MELF(+)/TB(-) (n = 15), MELF(+)/TB(+) (n = 20), and MELF(-)/TB(-) (n = 96). Adverse pathological features were observed in the MELF(+)/TB(+) group: 70% presented deep muscular infiltration, 65% were lymphovascular space invasion, and 25% suffered lymph node metastasis. The proportion of MMR deficient in MELF(+)/TB(-) group was the highest (66.7%). The progression-free survival (PFS) and overall survival (OS) among the four groups were significantly different. MELF(+)/TB(+) group showed the worst PFS and OS. As univariate and multivariate survival analyses revealed, the combination of MELF pattern and TB was confirmed as an independent predictor of poor prognosis.

CONCLUSIONS

Our research demonstrates that MELF pattern combined with TB, as an independent predictor of adverse outcome, is associated with adverse pathological features, which facilitates better understanding of EEC tumor behavior and more precise prognosis without additional medical expense.

Sentinel Nodal Metastasis Detection in Endometrial Carcinoma With Microcystic, Elongated, and Fragmented (MELF) Pattern by Cytokeratin Immunostaining

OBJECTIVES

The microcystic, elongated, and fragmented (MELF) pattern of myoinvasion in endometrial carcinoma (EC) is associated with an increased risk of lymph node metastasis. Our aim is to assess the role of cytokeratin immunohistochemical (IHC) stains in detecting sentinel nodal metastasis in MELF pattern tumors.

METHODS

We recovered 19 MELF pattern EC hysterectomies with lymphadenectomy from our files. Negative nodes were subjected to cytokeratin AE1/AE3 IHC. Ten additional cases with sentinel lymph node (SLN) biopsies primarily assessed by IHC were also analyzed.

RESULTS

Of the 19 cases of EC, 6 had positive lymph nodes based on H&E-stained sections at the time of their initial diagnosis. With the addition of IHC stains, 8 previously negative cases were found to have node metastases, and 3 of these were SLNs. Among the 10 cases primarily assessed by IHC, 5 had malignant cells in their SLNs.

CONCLUSIONS

Cytokeratin IHC staining detected malignant cells in 9 of 16 cases with SLNs in our sample of women with MELF pattern of myoinvasion. Immunohistochemical stains should be routinely performed on SLNs from all MELF-positive cases to detect occult lymph node metastases and isolated tumor cells.

Pathological features, immunoprofile and mismatch repair protein expression status in uterine endometrioid carcinoma: focus on MELF pattern of myoinvasion

AIMS

Microcystic, elongated, and fragmented (MELF) pattern of myoinvasion has been related with increased risk of lympho-vascular space invasion (LVSI) and lymph node metastasis. We analysed a cohort of endometrioid endometrial carcinomas (EECs) to examine the relationships between the MELF pattern of invasion and the clinico-pathological and immunohistochemical features of EEC.

METHODS AND RESULTS

129 EECs were evaluated for the presence of MELF pattern and immunohistochemically tested for Mismatch repair (MMR) proteins, p16, p53 and beta-catenin. We observed 28 MELF + EECs and 101 MELF- EECs. LVSI was observed in 20 MELF + cases and in MELF- tumors. Lymph-node metastases were observed in 7 MELF + cases (2 macrometastases, 3 micrometastases and 2 ITCs). None of the MELF- cases showed micrometastases or ITCs, 18 cases had macrometastatic lymph-nodes. Statistical analysis showed that MELF + tumors carry an increased risk of developing nodal metastasis independent of tumor dimension and LVSI. Loss of MMR proteins expression was observed in 11 MELF + cases and 45 MELF- cases, respectively. Our data showed a higher frequency of immunohistochemical MLH1-PMS2 loss in MELF- pattern of invasion (32.67% of MELF- cases vs 21.43% of MELF + cases) but a higher prevalence of MSH2-MSH6 loss in MELF + pattern (7.14% in MELF + population vs 3.96% of MELF- population) CONCLUSIONS: The morphological recognition of MELF pattern is more reliable than immunohistochemical and molecular signatures of EEC in predicting the risk of nodal involvement. The observed higher prevalence of MSH2-MSH6 loss in MELF + group and MLH1-PMS2 loss in MELF- group may suggest a different molecular signature.

Microcystic, Elongated and Fragmented Pattern Invasion Can Adversely Influence Preoperative Staging for Low-grade Endometrial Carcinoma

Purpose:

To investigate the influence of microcystic, elongated and fragmented (MELF) pattern invasion on preoperative evaluation of lymph node (LN) metastasis and myometrial invasion in patients with low-grade endometrial carcinoma.

Methods:

The study included 192 consecutive patients with low-grade endometrial carcinoma who underwent preoperative computed tomography (CT) and magnetic resonance imaging (MRI), followed by surgery. One hundred sixty one of 192 patients underwent LN dissection and were analyzed for LN metastasis. All patients were analyzed for myometrial invasion. Presence of enlarged LN was evaluated by using size criteria on CT. Depth of myometrial invasion was evaluated on MRI using T₂-weighted imaging, diffusion-weighted imaging and contrast-enhanced T₁-weighted imaging comprehensively. Sensitivity and specificity for LN metastasis and deep myometrial invasion were evaluated for MELF group and non-MELF group. The difference of sensitivity between two groups was compared using Chi-square and Fisher’s exact test.

Results:

MELF pattern invasion was identified in 43/192 patients (22%). LN metastases were observed in 18/39 patients in MELF group and 6/122 patients in non-MELF group for pelvic LN and 11/29 patients in MELF group and 4/57 patients in non-MELF group for para-aortic LN. Sensitivity for the detection of pelvic LN metastasis in MELF group was significantly lower than in non-MELF group (16.7% vs 66.7%). As for the assessment of the deep myometiral invasion, pathological deep myometrial invasion were found in 31/43 patients in MELF group and 32/149 patients in non-MELF group. Sensitivity in MELF group showed lower values than in non-MELF group (54.8% vs 78.1% for reader 1, 54.8% vs 62.5% for reader 2), although there was no statistically significant difference (P = 0.09 for reader 1 and P = 0.72 for reader 2).

Conclusion:

In case of low-grade endometrial carcinoma with MELF pattern invasion, preoperative staging by CT and MRI have a risk for underestimation.

Myoinvasive Pattern as a Prognostic Marker in Low-Grade, Early-Stage Endometrioid Endometrial Carcinoma

Low-grade and early Federation for Gynecology and Obstetrics (FIGO) stage endometrioid endometrial carcinomas (EEC) have an excellent prognosis. However, approximately 10% of patients develop recurrence, which cannot be correctly predicted at diagnosis. We evaluated myoinvasive patterns as a prognostic factor of relapse in low-grade, early-stage EEC. Two-hundred and fifty-eight cases were selected according to the following inclusion criteria: (i) endometrioid endometrial carcinomas, (ii) grade 1 or 2 with (iii) FIGO stage I or II, and (iv) clinical follow-up. Slides were reviewed to annotate the myoinvasive pattern present in each case (infiltrative glands, microcystic, elongated and fragmented -MELF-, broad front, adenomyosis-like and adenoma malignum). Microsatellite instability was studied by immunoexpression of mismatch repair proteins (MLH1, PMS2, MSH2, and MSH6). There were 29 recurrences (11.2%) among the 258 cases analysed. A predominant broad front myoinvasive pattern was significantly associated with tumour relapse (p = 0.003). The presence of a pattern of infiltrative glands (p = 0.001) and microsatellite instability (p = 0.004) were associated with lower disease-free survival, without having an impact on overall survival. Our observations suggest the potential value of the pattern of myoinvasion as a prognostic factor in low-grade, early-stage endometrioid endometrial carcinoma.

High Expression of Galectin-1, VEGF and Increased Microvessel Density Are Associated with MELF Pattern in Stage I-III Endometrioid Endometrial Adenocarcinoma

Background

In this study, we investigate the expression of markers of angiogenesis and microvessel density (MVD) in cases of microcystic, elongated and fragmented (MELF) pattern, with its prognostic role in the survival of endometrioid endometrial adenocarcinomas (EA) patients.

Methods

In this study, 100 cases of EA, 49 cases with MELF pattern and 51 without, were immunohistochemically stained for galectin-1, vascular endothelial growth factor (VEGF), and MVD. Morphometry and statistical (univariate and multivariate) analyses were performed to assess overall survival (OS) and disease-free survival.

Results

The expression of VEGF (p<.001) and galectin-1 (p<.001), as well as MVD area (p<.001) and number of vessels/mm² (p<.050), were significantly higher in the +MELF pattern group compared to the –MELF group. A low negative correlation between MELF-pattern and the number of days of survival (p<.001, r=–0.47) was also found. A low positive correlation of MELF-pattern with galectin-1 expression (p<.001, r=0.39), area of vessels/mm² (p<.001, r=0.36), outcome of EA (p<.001, r=0.42) and VEGF expression (p<.001, r=0.39) suggests potential pathological relevance of these factors in the prognosis of EA. A univariate survival analysis indicated a role for all parameters of survival. Multivariate Cox proportional hazard regression analysis revealed that only area of vessels/mm² (hazard ratio [HR], 1.018; 95% confidence interval [CI], 1.002 to 1.033), galectin-1 (HR, 1.049; 95% CI, 1.025 to 1.074) and VEGF (HR, 1.049; 95% CI, 1.022 to 1.077) play key roles in OS.

Conclusions

This study reports an increase in MVD, VEGF and galectin-1 expression in EA with MELF pattern and suggests that MELF pattern, along with the angiogenic profile, may be a prognostic factor in EA.

Active K-RAS induces the coherent rotation of epithelial cells: A model for collective cell invasion in vitro

At the invasive front of adenocarcinomas, single cells and multicellular structures exist; the latter include glands and cell clusters, such as tumor buddings and poorly differentiated clusters. Recent reports suggest the importance of collective cell migration in metastasis; however, it is technically difficult to observe the movement of multicellular structures in vivo. We utilized MDCK cells as a model for epithelial cells and established a method to quantify their motility in 3D structures in vitro. A single MDCK cell grows as a cell cluster in the gel and later proliferates and forms a cyst. Active K-RAS expression induced rotation of both the cell clusters and the cysts. The rotation speed of cell clusters was 4 times higher than that of cysts. The screening of inhibitors for their effects on cell clusters and cysts revealed that cyclin B1 and β-catenin were the key molecules for their rotation, respectively. Regulators for cyst rotation, such as vorinostat and β-catenin, were not effective for inducing cell cluster rotation. These results indicate that the signaling pathways of cell dynamics are different between cell clusters and cysts. As cell clusters are related to lymph node involvement and the prognosis of various carcinomas, our in vitro quantitative system may be useful for the screening of drugs to prevent lymphatic invasion.

MELF pattern of myometrial invasion and role in possible endometrial cancer diagnostic pathway: A systematic review of the literature

Microcystic, elongated, fragmented (MELF) pattern of myometrial invasion has been proposed as a prognostic marker in patients with endometrial carcinoma (EC). Its prognostic and predictive effect still remains elusive. The aim of the present study is to accumulate the current knowledge on the role of MELF pattern in the prognosis and survival of patients with EC. Medline, Scopus, Google Scholar, and Clinicaltrials.gov databases were searched for articles published up to May 2018, along with the references of all articles. Prospective and retrospective trials reporting outcomes of cases with EC who were examined for MELF pattern were considered eligible for inclusion in the present systematic review. Of the 196 records screened, 14 were considered eligible. A total of 14 studies which comprised 588 women were finally included in the present systematic review. All the included patients were evaluated for presence of MELF pattern of myometrial invasion. MELF positive (+) patients were more likely to present with larger and higher grade tumors, lymph node metastasis, lymphovascular invasion and >50% myometrial invasion. No difference was reported in disease free survival (DFS) and disease specific survival (DSS) as well as in vaginal recurrence rates. MELF (+) was reported as a significant indicator of survival. In conclusion, MELF pattern of myometrial invasion plays a critical role in lymphovascular space invasion and lymph node metastasis in patients with EC. Regardless, its implication in survival and recurrences is ill determined.

Disseminated tumor cells are not associated with established risk factors, L1CAM immunoreactivity and outcome in endometrial carcinoma

PURPOSE

The presence of disseminated tumor cells (DTC) in the bone marrow of endometrial carcinoma patients has been demonstrated previously. In contrast to breast cancer, no prognostic significance or association with clinicopathological features was revealed for endometrial carcinoma so far. The aim of this study was to investigate DTC in a large patient cohort with in-depth pathology review data available and to study DTC occurrence in the context of L1CAM and long-term disease specific follow-up.

METHODS

Patients treated for endometrial carcinoma at the Tuebingen University Women's hospital between 2003 and 2013 were identified. Cases with previous expert central pathology review including L1CAM immunohistochemistry and bone marrow aspirates available were selected. The presence of DTC and L1CAM expression was studied immunohistochemically.

RESULTS

In 395 cases with a confirmed diagnosis of endometrial carcinoma, bone marrow aspirates were available. DTC were detected in 17.2%. The presence of DTC was independent from tumor histology, grade, lymphovascular space involvement (LVSI), FIGO stage, myoinvasion, L1CAM immunoreactivity, and nodal metastasis. DTC occurred less frequently in cases with a microcystic elongated and fragmented (MELF) pattern of invasion (2.2 vs. 21.8%, p = 0.0003). Disease progression was distributed equally among patients with and without DTC present.

CONCLUSIONS

We were able to confirm previous findings of DTC presence in a large well-characterized cohort of endometrial carcinoma patients. DTC are detectable in almost one-fifth of endometrial carcinoma and occur less frequently with a MELF pattern of invasion. Further studies investigating the role of DTC in endometrial carcinoma are warranted.