Lien N Hoang

POLE exonuclease domain mutation predicts long progression-free survival in grade 3 endometrioid carcinoma of the endometrium.

OBJECTIVE POLE exonuclease domain mutations were recently found to occur in a subset of endometrial carcinomas and result in defective proof-reading function during DNA replication. The aim of this study is to further characterize the clinical and pathologic significance of POLE exonuclease domain mutations in high-grade endometrial carcinomas. METHODS We assessed for mutations in the exonuclease domain of POLE by Sanger sequencing in 53 grade 3 endometrioid, 25 serous, 16 clear cell and 5 dedifferentiated carcinomas. We correlated POLE mutation status with clinicopathologic features and molecular parameters. Univariate and multivariate survival analyses were performed using Kaplan-Meier and cox regression analyses. RESULTS POLE exonuclease domain mutations were identified in 8 of 53 (15%) grade 3 endometrioid carcinomas and not in any other histotypes examined. Only 1 of the 8 grade 3 endometrioid carcinomas with POLE exonuclease domain mutation displayed deficient mismatch repair protein expression by immunohistochemistry (MSH6 loss), compared to 21 of 45 grade 3 endometrioid carcinomas with wild-type exonuclease domain. When analyzed together with published grade 3 endometrioid carcinomas by The Cancer Genome Atlas, the presence of POLE exonuclease domain mutation was associated with significantly better progression-free survival in univariate (p=0.025) and multivariate (p=0.010) analyses, such that none of the patients with POLE mutated tumors experienced disease progression CONCLUSIONS POLE exonuclease domain mutations occur in a subset of grade 3 endometrioid carcinomas and are associated with good clinical outcome. It can serve as an important prognostic molecular marker to guide the management of patients with grade 3 endometrioid carcinomas.

Histotype-genotype correlation in 36 high-grade endometrial carcinomas.

Endometrioid, serous, and clear cell carcinomas are the major types of endometrial carcinoma. Histologic distinction between these different tumor types can be difficult in high-grade cases, in which significant interobserver diagnostic disagreement exists. Endometrioid and clear cell carcinomas frequently harbor ARID1A and/or PTEN mutations. Serous carcinoma acquires TP53 mutations/inactivation at onset, with a significant subset harboring an additional mutation in PPP2R1A. This study examines the correlation between tumor histotype and genotype in 36 previously genotyped high-grade endometrial carcinomas. This included 23 endometrioid/clear cell genotype and 13 serous genotype tumors. Eight subspecialty pathologists reviewed representative online slides and rendered diagnoses before and after receiving p53, p16, and estrogen receptor immunostaining results. &kgr; statistics for histotype-genotype concordance were calculated. The average &kgr; values for histotype-genotype concordance was 0.55 (range, 0.30 to 0.67) on the basis of morphologic evaluation alone and it improved to 0.68 (range, 0.54 to 0.81) after immunophenotype consideration (P<0.001). Genotype-incompatible diagnoses were rendered by at least 2 pathologists in 12 of 36 cases (33%) (3 cases by 2/8 pathologists, 2 by 3/8, 2 by 4/8, 3 by 6/8, 1 by 7/8, and 1 case by 8/8 pathologists). Six of the 12 were endometrioid/clear cell genotype tumors, and the other 6 were serous genotype tumors. The histopathologic features associated with histotype-genotype–discordant cases were reviewed, and specific diagnostic recommendations were made to improve concordance. This study found that although the majority of morphologic diagnoses are genotype concordant, genotype-incompatible diagnoses are made in a significant subset of cases. Judicious use and interpretation of p53 immunohistochemistry in selected scenarios can improve histotype-genotype concordance.

Targeted mutation analysis of endometrial clear cell carcinoma

Endometrial clear cell carcinomas (CCC) constitute fewer than 5% of all carcinomas of the endometrium. Currently, little is known regarding the genetic basis of endometrial CCC.

Immunohistochemical characterization of prototypical endometrial clear cell carcinoma—diagnostic utility of HNF-1β and oestrogen receptor

The great majority of ovarian clear cell carcinomas have a hepatocyte nuclear factor 1 homeobox B (HNF‐1β)‐positive and oestrogen receptor (ER)‐negative immunoprofile. However, the pattern of HNF‐1β and ER immunostaining in clear cell carcinomas of the endometrium and the usefulness of this panel in distinguishing clear cell carcinoma from other histological types of endometrial carcinoma have yet to be well defined.

Frequent expression of KIT in endometrial stromal sarcoma with YWHAE genetic rearrangement

Endometrial stromal sarcomas with the YWHAE-NUTM2A/B genetic fusion characteristically contain high-grade round to epithelioid cell component that is strongly and diffusely cyclin D1-positive and it may or may not show an associated low-grade fibroblastic/myxoid cell component. They are clinically more aggressive than endometrial stromal sarcomas with the JAZF1-SUZ12 genetic fusion and frequently demonstrate extrauterine extension at initial clinical presentation. In this setting, the tumor may be misdiagnosed as gastrointestinal stromal tumor. This study examines the expression of KIT and ANO1 in 14 YWHAE-NUTM2A/B tumors by immunohistochemistry. Staining localization was determined as membranous and/or cytoplasmic, and the staining intensity was assessed (negative, weak, moderate and strong). Of the 14 tumors, 6 contained only a high-grade round cell component, 2 only a low-grade fibroblastic component and 6 had both components in the slides evaluated. The high-grade round cell component displayed moderate to strong membranous/cytoplasmic KIT staining in all tumors (12 of 12). The low-grade fibroblastic cell component showed only weak cytoplasmic KIT staining in 3 of 8 tumors. In contrast, ANO1 was negative in all 14 neoplasms, irrespective of the component evaluated. Sanger sequencing analysis (exons 9, 11, 13 and 17) and Ampliseq Cancer Panel mutation screen (Ion Torrent) demonstrated no KIT mutations in three KIT-positive YWHAE-NUTM2A/B tumors. This study shows that the high-grade round cell component of YWHAE-NUTM2A/B endometrial stromal sarcoma consistently expresses KIT but lacks KIT hotspot mutations. KIT expression may represent a potential diagnostic pitfall in the evaluation of YWHAE-NUTM2A/B endometrial stromal sarcoma presenting with pelvic/abdominal mass, particularly in situations where its uterine origin is not definitive, and thus a panel of antibodies that includes ANO1 and cyclin D1 is necessary.

Loss of switch/sucrose non-fermenting complex protein expression is associated with dedifferentiation in endometrial carcinomas.

Dedifferentiated endometrial carcinoma is an aggressive type of endometrial cancer that contains a mix of low-grade endometrioid and undifferentiated carcinoma components. We performed targeted sequencing of eight dedifferentiated carcinomas and identified somatic frameshift/nonsense mutations in SMARCA4, a core ATPase of the switch/sucrose non-fermenting (SWI/SNF) complex, in the undifferentiated components of four tumors. Immunohistochemical analysis confirmed the loss of SMARCA4 in the undifferentiated component of these four SMARCA4-mutated cases, whereas the corresponding low-grade endometrioid component showed retained SMARCA4 expression. An expanded survey of other members of the SWI/SNF complex showed SMARCB1 loss in the undifferentiated component of two SMARCA4-intact tumors, and all SMARCA4- or SMARCB1-deficient tumors showed concomitant loss of expression of SMARCA2. We subsequently examined the expression of SMARCA2, SMARCA4, and SMARCB1 in an additional set of 22 centrally reviewed dedifferentiated carcinomas and 31 grade 3 endometrioid carcinomas. Combining the results from the index and the expansion set, 15 of 30 (50%) of the dedifferentiated carcinomas examined showed either concurrent SMARCA4 and SMARCA2 loss (37%) or concurrent SMARCB1 and SMARCA2 loss (13%) in the undifferentiated component. The loss of SMARCA4 or SMARCB1 was mutually exclusive. All 31 grade 3 endometrioid carcinomas showed intact expression of these core SWI/SNF proteins. The majority (73%) of the SMARCA4/SMARCA2-deficient and half of SMARCB1/SMARCA2-deficient undifferentiated component developed in a mismatch repair-deficient molecular context. The observed spatial association between SWI/SNF protein loss and histologic dedifferentiation suggests that inactivation of these core SWI/SNF proteins may contribute to the development of dedifferentiated endometrial carcinoma.

YWHAE-FAM22 endometrial stromal sarcoma: diagnosis by reverse transcription–polymerase chain reaction in formalin-fixed, paraffin-embedded tumor ☆ ☆☆

A subset of endometrial stromal sarcoma harbors t(10;17)(q23;p13), which results in the genetic fusion between YWHAE and 1 of 2 highly homologous FAM22 family members-FAM22A or FAM22B. In contrast to classic low-grade endometrial stromal sarcoma with JAZF1-SUZ12 fusions, YWHAE-FAM22 endometrial stromal sarcoma displays high-grade histologic features and is associated with more aggressive disease course. Ancillary fluorescence in situ hybridization assay demonstrating the presence of YWHAE rearrangement can be used to support the diagnosis, but the detection of fusion transcript would be the most definitive test. We describe here an optimized reverse transcription-polymerase chain reaction assay for detection of YWHAE-FAM22 fusion transcript in formalin-fixed and paraffin-embedded tumor samples. We studied a series of 6 YWHAE-FAM22 endometrial stromal sarcomas, 7 JAZF-SUZ12 endometrial stromal sarcomas, 3 JAZF1-PHF1/EPC1-PHF1 endometrial stromal sarcomas, 6 undifferentiated endometrial sarcomas, 4 uterine leiomyosarcomas, and 4 uterine adenosarcomas. All 6 YWHAE-FAM22 endometrial stromal sarcomas were confirmed by fluorescence in situ hybridization assay, whereas all non-YWHAE-FAM22 tumors were confirmed to lack YWHAE rearrangement by fluorescence in situ hybridization assay. The reverse transcription-polymerase chain reaction assay optimized for formalin-fixed and paraffin-embedded samples detected YWHAE-FAM22 fusion transcripts in all 6 YWHAE-FAM22 endometrial stromal sarcomas and none of the 24 non-YWHAE-FAM22 uterine sarcomas. These findings show that this reverse transcription-polymerase chain reaction assay is sensitive and specific for detection of YWHAE-FAM22 fusion transcript and can serve as a useful adjunct diagnostic assay to confirm the diagnosis of YWHAE-FAM22 endometrial stromal sarcoma in formalin-fixed and paraffin-embedded tumor samples.

Histopathological features of endometrial carcinomas associated with POLE mutations: implications for decisions about adjuvant therapy

To characterize the histomorphological features of endometrial carcinomas (ECs) harbouring polymerase ε (POLE) mutations.

Molecular Analysis of Mixed Endometrial Carcinomas Shows Clonality in Most Cases.

Mixed endometrial carcinoma refers to a tumor that comprises 2 or more distinct histotypes. We studied 18 mixed-type endometrial carcinomas—11 mixed serous and low-grade endometrioid carcinomas (SC/EC), 5 mixed clear cell and low-grade ECs (CCC/EC), and 2 mixed CCC and SCs (CCC/SC), using targeted next-generation sequencing and immunohistochemistry to compare the molecular profiles of the different histotypes present in each case. In 16 of 18 cases there was molecular evidence that both components shared a clonal origin. Eight cases (6 EC/SC, 1 EC/CCC, and 1 SC/CCC) showed an SC molecular profile that was the same in both components. Five cases (3 CCC/EC and 2 SC/EC) showed a shared endometrioid molecular profile and identical mismatch-repair protein deficiency in both components. A single SC/EC case harbored the same POLE exonuclease domain mutation in both components. One SC/CCC and 1 EC/CCC case showed both shared and unique molecular features in the 2 histotype components, suggesting early molecular divergence from a common clonal origin. In 2 cases, there were no shared molecular features, and these appear to be biologically unrelated synchronous tumors. Overall, these results show that the different histologic components in mixed endometrial carcinomas typically share the same molecular aberrations. Mixed endometrial carcinomas most commonly occur through morphologic mimicry, whereby tumors with serous-type molecular profile show morphologic features of EC or CCC, or through underlying deficiency in DNA nucleotide repair, with resulting rapid accrual of mutations and intratumoral phenotypic heterogeneity. Less commonly, mixed endometrial carcinomas are the result of early molecular divergence from a common progenitor clone or are synchronous biologically unrelated tumors (collision tumors).

Novel High-grade Endometrial Stromal Sarcoma: A Morphologic Mimicker of Myxoid Leiomyosarcoma.

Endometrial stromal sarcomas (ESS) are often underpinned by recurrent chromosomal translocations resulting in the fusion of genes involved in epigenetic regulation. To date, only YWHAE-NUTM2 rearrangements are associated with distinctive high-grade morphology and aggressive clinical behavior. We identified 3 ESS morphologically mimicking myxoid leiomyosarcoma of the uterus and sought to describe their unique histopathologic features and identify genetic alterations using next-generation sequencing. All cases displayed predominantly spindled cells associated with abundant myxoid stroma and brisk mitotic activity. Tumors involved the endometrium and demonstrated tongue-like myometrial infiltration. All 3 were associated with an aggressive clinical course, including multisite bony metastases in 1 patient, progressive peritoneal disease after chemotherapy in another, and metastases to the lung and skin in the last patient. All 3 ESS were found to harbor ZC3H7B-BCOR gene fusions by targeted sequencing and fluorescence in situ hybridization. On the basis of the review of these cases, we find that ESS with ZC3H7B-BCOR fusion constitutes a novel type of high-grade ESS and shares significant morphologic overlap with myxoid leiomyosarcoma.