IFITM1 Is Superior to CD10 as a Marker of Endometrial Stroma in the Evaluation of Myometrial Invasion by Endometrioid Adenocarcinoma

Ectopic Endometrium: The Pathologist's Perspective

Endometriosis and adenomyosis are two frequent diseases closely linked, characterized by ectopic endometrium. Despite their benign nature, endometriosis and adenomyosis impair women's quality of life by causing pain and infertility and an increase in the incidence of gynecological malignancies has been reported. Since the first description of ectopic endometrium in 1860, different attempts have been made to describe, classify and understand the origin of these diseases. Several theories have been proposed to describe the pathogenic mechanism leading to the development of adenomyosis or endometriosis. However, all the hypotheses show some limitations in explaining all the different aspects and manifestations of these diseases. Despite the remarkable progress made over recent years, the pathogeneses of endometriosis and adenomyosis remain unclear. Moreover, because of the lack of standardized protocols and diagnostic criteria in pathology practice it is difficult to study and to classify these disorders. The goal of this review is to summarize the pathological aspects of adenomyosis and endometriosis, spanning a historical perspective to newly reported data.

[Endometriosis and adenomyosis]

Diffuse adenomyosis, focal adenomyosis, ovarian endometrioma, superficial endometriosis and deep infiltrating adenomyosis are all defined by the presence of an endometrioid tissue in an ectopic location that is at distance from the endometrium. Although frequently associated, these lesions represent different clinico-pathological entities that the pathologist should recognized. Herein, we review the clinical and pathological features of these entities, as well as related current physiopathological understandings and differential diagnoses that could be raised by some morphological variants. The statistical association between endometriosis and several ovarian tumors, mainly endometrioid and clear cell carcinomas and seromucinous borderline tumors is well established and we present some molecular and morphological features that support this transformation potential.

Characterization of the Endometrial MSC Marker Ectonucleoside Triphosphate Diphosphohydrolase-2 (NTPDase2/CD39L1) in Low- and High-Grade Endometrial Carcinomas: Loss of Stromal Expression in the Invasive Phenotypes

Ectonucleoside triphosphate diphosphohydrolase-2 (NTPDase2/CD39L1) has been described in human non-pathological endometrium in both epithelial and stromal components without changes along the cycle. It was identified as a stromal marker of basalis. In the present study, we aimed to evaluate NTPDase2 distribution, using immunolabeling and in situ enzyme activity approaches, in endometrial carcinoma (EC) at different tumor grades. NTPDase2 was present in tumor epithelial EC cells, as in the non-pathological endometria, but the expression underwent changes in subcellular distribution and also tended to decrease with the tumor grade. In stroma, NTPDase2 was identified exclusively at the tumor-myometrial junction but this expression was lost in tumors of invasive phenotype. We have also identified in EC samples the presence of the perivascular population of endometrial mesenchymal stem cells (eMSCs) positive for sushi domain containing 2 (SUSD2) and for NTPDase2, already described in non-tumoral endometrium. Our results point to NTPDase2 as a histopathological marker of tumor invasion in EC, with diagnostic relevance especially in cases of EC coexisting with other endometrial disorders, such as adenomyosis, which occasionally hampers the assessment of tumor invasion parameters.

IFITM1 is a Novel, Highly Sensitive Marker for Endometriotic Stromal Cells in Ovarian and Extragenital Endometriosis

When the presence of endometriotic lesions are not evident by hematoxylin and eosin staining, CD10 is used to highlight and confirm the presence of endometriotic stroma. However, CD10 is not specific only to the endometrial stroma but is also expressed in many other cells. Recently, interferon-inducible transmembrane protein 1 (IFITM1) was reported as a highly specific immunohistochemical marker of normal endometrial stroma and endometrial stromal neoplasm. In this study, we examined the expression of IFITM1 and CD10 in 18 cases of ovarian endometriosis and 44 cases of extragenital endometriosis. Among the 62 patients, 62 (100.0%) were positive for IFITM1 and 60 (96.8%) for CD10, and CD10 was negative in 2 cases that were positive for IFITM1. Additionally, we found that IFITM1 sensitivity was unaffected by the presence or absence of hormonal therapy. To the best of our knowledge, this represents the first demonstration of IFITM1 as a highly sensitive stromal marker of ovarian and extragenital endometriosis.

The Crowded Crosstalk between Cancer Cells and Stromal Microenvironment in Gynecological Malignancies: Biological Pathways and Therapeutic Implication

The tumor microenvironment plays a pillar role in the progression and the distance dissemination of cancer cells in the main malignancies affecting women-epithelial ovarian cancer, endometrial cancer and cervical cancer. Their milieu acquires specific properties thanks to intense crosstalk between stromal and cancer cells, leading to a vicious circle. Fibroblasts, pericytes, lymphocytes and tumor associated-macrophages orchestrate most of the biological pathways. In epithelial ovarian cancer, high rates of activated pericytes determine a poorer prognosis, defining a common signature promoting ovarian cancer proliferation, local invasion and distant spread. Mesenchymal cells also release chemokines and cytokines under hormonal influence, such as estrogens that drive most of the endometrial cancers. Interestingly, the architecture of the cervical cancer milieu is shaped by the synergy of high-risk Human Papilloma Virus oncoproteins and the activity of stromal estrogen receptor α. Lymphocytes represent a shield against cancer cells but some cell subpopulation could lead to immunosuppression, tumor growth and dissemination. Cytotoxic tumor infiltrating lymphocytes can be eluded by over-adapted cancer cells in a scenario of immune-tolerance driven by T-regulatory cells. Therefore, the tumor microenvironment has a high translational potential offering many targets for biological and immunological therapies.

IFITM1 is a Novel, Highly Sensitive Marker for Endometriotic Stromal Cells in Ovarian and Extragenital Endometriosis

When the presence of endometriotic lesions are not evident by hematoxylin and eosin staining, CD10 is used to highlight and confirm the presence of endometriotic stroma. However, CD10 is not specific only to the endometrial stroma but is also expressed in many other cells. Recently, interferon-inducible transmembrane protein 1 (IFITM1) was reported as a highly specific immunohistochemical marker of normal endometrial stroma and endometrial stromal neoplasm. In this study, we examined the expression of IFITM1 and CD10 in 18 cases of ovarian endometriosis and 44 cases of extragenital endometriosis. Among the 62 patients, 62 (100.0%) were positive for IFITM1 and 60 (96.8%) for CD10, and CD10 was negative in 2 cases that were positive for IFITM1. Additionally, we found that IFITM1 sensitivity was unaffected by the presence or absence of hormonal therapy. To the best of our knowledge, this represents the first demonstration of IFITM1 as a highly sensitive stromal marker of ovarian and extragenital endometriosis.

IFITM1 Outperforms CD10 in Differentiating Low-grade Endometrial Stromal Sarcomas From Smooth Muscle Neoplasms of the Uterus

Distinguishing between uterine neoplasms of smooth muscle and endometrial stromal origin is a frequent diagnostic challenge. We investigated the staining pattern of interferon-induced transmembrane protein-1 (IFITM1), a novel endometrial stromal marker, in endometrial and smooth muscle uterine neoplasms and compared it with CD10 in its ability to differentiate between these two groups. Immunohistochemistry for IFITM1 and CD10 was performed in 20 cases of smooth muscle neoplasms (10 cases leiomyoma, 10 cases leiomyosarcoma), 14 cases of endometrial stromal sarcoma (ESS) (12 cases of low grade and 2 cases of high grade) and 12 cases of carcinosarcoma. Staining was scored in terms of intensity and distribution (0=absent, 1=weak/<50%, 2=moderate/50%-75%, 3=strong/>75%). A total score was obtained by adding intensity and distribution scores and classified as positive (score 3-6) or negative (score 0-2). IFITM1 was positive in 10 of 12 (83%) low-grade ESSs, 6 of 20 (30%) smooth muscle tumors (leiomyomas and leiomyosarcomas) and 11 of 12 carcinosarcomas (91.6%). The 2 cases of high-grade ESS were IFITM1 negative. While both IFITM1 (83%) and CD10 (91%) had high sensitivity in differentiating low-grade ESSs from smooth muscle neoplasms, IFITM1 (70%) had higher specificity compared with CD10 (45%). In this study IFITM1 appears to be a more specific marker of endometrial stromal differentiation compared with CD10 in differentiating low-grade ESSs from smooth muscle neoplasms. Thus, IFITM1 may be a valuable tool as part of an immunohistochemical evaluation panel in this diagnostic scenario.

Combination of IFITM1 knockdown and radiotherapy inhibits the growth of oral cancer

This research aimed to analyze the effect of IFITM1 on the radioresistance of oral neoplasm. Using a multi‐group heat map from GSE9716 analysis of the GEO database, IFITM1 was determined to be a relevant radioresistance gene. The TCGA database was analyzed before the expression of IFITM1 was analyzed. IFITM1 expression was quantified by quantitative RT‐PCR and immunohistochemistry in 19 paired oral neoplasm cases. The effects of time and dose of radiation on IFITM1 expression level in CAL27 and TSCC1 cell lines were tested by quantitative RT‐PCR. Oral neoplasm cells were transfected with siRNA after radiotherapy to disturb IFITM1 expression. After this, the survival rates, cell apoptosis, caspase‐3 viability, expression and γ‐H2AX were detected using colony formation, flow cytometry, western blot and immunofluorescence, respectively. Western blot was used for STAT1/2/3/p21‐related protein and phosphorylation changes. Finally, an in vivo nude mice tumor model was established to verify the effect of IFITM1 on oral neoplasm cells radioresistance. Through microarray analysis, the head and neck neoplasm radioresistance‐related gene IFITM1 was found to be overexpressed. IFITM1 overexpression was verified not only using the TCGA database but also in 19 paired cases of oral neoplasm tissues and cells. With increases of dose and time of radiation, the expression of IFITM1 was increased in CAL27 and TSCC1 cell lines. Furthermore, si‐IFITM1 may restrain cell proliferation, DNA damage and cell apoptosis in oral neoplasm cell lines. Finally, pSTAT1/2/p21 was found to be upregulated while pSTAT3/p‐p21 was downregulated due to IFITM1 inhibition after radiotherapy. The evidence suggested that IFITM1 in combination with radiotherapy can inhibit oral neoplasm cells.