The proto-oncogene c-kit is expressed in leiomyosarcomas of the uterus

Pathophysiological Implications of Interstitial Cajal-like Cells (ICC-like) in Uterus: A Comparative Study with Gastrointestinal ICCs

The main function of interstitial cells of Cajal (ICCs) is to regulate gastrointestinal peristalsis by acting as a "pacemaker" cell by generating spontaneous slow electrical waves. In 2005, electron microscopy revealed a cell type similar to ICCs (ICC-like) outside the gastrointestinal tract, with contractile activity and c-Kit+ immunohistochemistry shared with ICCs. Among the locations where ICC-like cells have been observed, it is in the uterus where they have a significant functional and pathophysiological role. These cells are involved in obstetric phenomena of contractile action, such as ascending sperm transport, embryo implantation, pregnancy, delivery, and the expulsion of menstrual debris. Within the pathophysiology related to these cells, we find obstetric alterations such as recurrent miscarriages, premature deliveries, abolition of uterine contractions, and failures of embryo implantation, in addition to other common conditions in the fertile age, such as endometriosis and leiomyoma.

Molecular Insights into Endometrial Cancer in Mice

Pluripotent, very small embryonic-like stem cells (VSELs) and the 'progenitors' endometrial stem cells (EnSCs) along with associated molecular changes in endometrial cancer, that developed seven months after neonatal exposure to estradiol in one of the sixty mice, were studied in the present study. Endocrine disruption affected both endometrium and myometrium, there was accumulation of endometrial fluid and significant hyperplasia. Disrupted endometrial-myometrial junction resulted in mobilization of myometrial cells into endometrium and epithelial and stromal cells into myometrium suggestive of adenomyosis. Markers specific for VSELs/ EnSCs (OCT-4, NANOG, SSEA-1, SCA-1, c-KIT) showed increased expression in uterine sections and marked upregulation of corresponding transcripts (Oct-4A, Oct-4, Sox-2, Nanog, Sca-1, c-Kit) was noted in RNA extracted from both uterine tissue and stem cells enriched from endometrial fluid. Hormonal receptors (ER-α, ER-β, PR, FSHR) were upregulated in both tumor sections and in endometrial fluid. ER-β and FSHR (Fshr3) expression was prominent suggesting a major role in endometrial cancer. Cancer cells showed global hypomethylation (reduced expression of 5-methyl cytosine), reduced expression of tumor suppressor gene (PTEN) and increased expression of cancer stem cells marker (CD166) which suggested dysregulation and aberrant oncogenic events. Increased expression of PCNA, Ki67, SOX-9 suggested excessive proliferation and hyperplasia which are predominant signs of endometrial cancer. Results suggest that VSELs increase in numbers and possibly transform into cancer stem cells (co-express CD166 and OCT-4) in endometrial cancer. Expression of OCT-4, CD133, ALDHA1 and CD166 in side-population cells from human endometrial cancer samples suggests a possible role of VSELs in human endometrial cancer as well.

RNA Sequencing for Personalized Treatment of Metastatic Leiomyosarcoma: Case Report

Uterine leiomyosarcoma (UL) is a rare malignant tumor that develops from the uterine smooth muscle tissue. Due to the low frequency and lack of sufficient data from clinical trials there is currently no effective treatment that is routinely accepted for UL. Here we report a case of a 65-years-old female patient with metastatic UL, who progressed on ifosfamide and doxorubicin therapy and developed severe hypertensive crisis after administration of second line pazopanib, which lead to treatment termination. Rapid progression of the tumor stressed the need for the alternative treatment options. We performed RNA sequencing and whole exome sequencing profiling of the patient's biopsy and applied Oncobox bioinformatic algorithm to prioritize targeted therapeutics. No clinically relevant mutations associated with drug efficiencies were found, but the Oncobox transcriptome analysis predicted regorafenib as the most effective targeted treatment option. Regorafenib administration resulted in a complete metabolic response which lasted for 10 months. In addition, RNA sequencing analysis revealed a novel cancer fusion transcript of YWHAE gene with fusion partner JAZF1. Several chimeric transcripts for YWHAE and JAZF1 genes were previously found in uterine neoplasms and some of them were associated with tumor prognosis. However, their combination was detected in this study for the first time. Taken together, these findings evidence that RNA sequencing may complement analysis of clinically relevant mutations and enhance management of oncological patients by suggesting putative treatment options.

[Interdisciplinary S2k guidelines on the diagnosis and treatment of uterine sarcomas-recommendations for surgical pathology]

Uterine sarcomas represent a heterogeneous group of rare malignancies, derived from the myometrium, the endometrial stroma, and very rarely from the nonspecialized uterine soft tissue. The actual incidence is about 1.5 for Caucasian and 3.0 for Afro-American women. There is no grading system for leimoysarcoma defined by the WHO classification; however, if clinicians request, the FNCLCC grading can be specified in analogy to soft tissue sarcomas. Adenosarcomas must be distinguished from adenofibromas (the existence of which is questionable)-with the vast majority of these tumors being uterine adenosarcomas. Within adenosarcomas, deep myometrial invasion (>50%), sarcomatous overgrowth, and a high-grade heterologous component are associated with a higher recurrence rate and poor survival. The immunohistochemical panel represents a very helpful tool for distinguishing low-grade from high grade endometrial stromal sarcomas (ESS) and may be supplemented by molecular analyses. Steroid hormone receptor analysis should be performed for all ESS due to the possible therapeutic relevance. Undifferentiated uterine sarcomas represent a diagnosis of exclusion and have a very poor prognosis. Carcinosarcomas represent a special subtype of endometrial carcinomas and are in fact not uterine sarcomas. Uterine sarcomas may present substantial intratumoral heterogeneity and adequate embedding is mandatory. Lesions ≤2 cm in the largest dimension should be processed completely and larger tumors should be processed with one block per centimeter for the largest tumor dimension.

Recently discovered interstitial cells "telocytes" as players in the pathogenesis of uterine leiomyomas

Uterine telocytes are interstitial cells characterized by a very long cytoplasmic prolongations, which form a 3D network, functionally integrating a wide variety of different cells. Leiomyomas (uterine fibroids) are benign tumors, which pose a huge threat concerning various health problems in women affected by this condition. The exact cause of leiomyomas development is, however, still largely unknown. Therefore, in an attempt to clarify their etiology, we performed an immunohistochemical characterization of telocytes in leiomyomas as well as in normal myometrium. Tissue samples of intramural leiomyomas from 26 women (age 46.26 ± 11.07) were immunohistochemically stained for the expression of c-kit (CD117) antigen, one of the markers of telocytes. C-kit (CD117) antigen is useful for a routine immunohistochemical identification of uterine telocytes in histological sections of myometrium. In normal, healthy myometrium the c-kit positive telocytes occupy approximately 2.2% of the area of a tissue slide, contrasting with no detectable c-kit positive cells within leiomyomas. As telocytes are thought to be key players in the regulation of tissue homoeostasis, our data suggest that uterine telocyte loss may have important implications in the pathogenesis of leiomyomas. In addition, we supposed to summarize three hypotheses on the association of the cells telocytes loss within the myometrium and formation of leiomyomas. These hypotheses include the loss of telocytes' functions as "sex hormone sensors" and regulators of smooth muscle cells cycle; the role of telocytes as progenitor cells for the development of leiomyomas; and the hypothesis of decreased angiogenesis after telocytes' loss with subsequent hypoxia (as a key factor for leiomyomas development).

Diagnostic use of immunohistochemistry in uterine mesenchymal tumors

Immunohistochemistry may be helpful in the diagnosis of mesenchymal uterine tumors. This article reviews the immunoreactions used most frequently in the diagnosis of uterine smooth muscle tumors, endometrial stromal tumors, undifferentiated endometrial sarcomas, UTROSCTs, PEComas, adenomyomas, adenosarcomas and carcinosarcomas.

Misdiagnosis of an extragastrointestinal stromal tumor in the rectovaginal septum

INTRODUCTION

Gastrointestinal stromal tumors are very rare, representing 0.1% to 1% of gastrointestinal malignancies. Gastrointestinal stromal tumors outside the digestive tract comprise a very small fraction of all gastrointestinal stromal tumors, and their most common locations are the omentum, the mesentery, and, in few cases, the rectovaginal septum. Despite their low incidence, extragastrointestinal stromal tumors are potentially malignant tumors and they present a high rate of recurrences. This, added to the fact that they are often asymptomatic until advanced stages, determines an unfavorable prognosis.

CASE REPORT

We report a case of gastrointestinal stromal tumor located in the rectovaginal septum, which recurred after local excision; hence, a reintervention was needed.

CONCLUSIONS

A correct differential diagnosis between extragastrointestinal stromal tumors and other similar pathologies such as leiomyomas or schwannomas is imperative based on their histology and immunohistochemistry. The correct diagnosis of extragastrointestinal stromal tumors allows to start adequate treatment and follow-up, preventing recurrence that determines their poor prognosis.

Tyrosine kinase receptor status in endometrial stromal sarcoma: an immunohistochemical and genetic-molecular analysis

Endometrial stromal sarcomas (ESS) are rare uterine malignant mesenchymal neoplasms, which are currently treated by surgery, as effective adjuvant therapies have not yet been established. Tyrosine kinase inhibitors have rarely been applied in ESS therapy, with few reports describing imatinib responsivity. The aim of this study was to analyze the status of different tyrosine kinase receptors in an ESS series, in order to evaluate their potential role as molecular targets. Immunohistochemistry was performed for EGFR, c-KIT, PDGFR-α, PDGFR-β, and ABL on 28 ESS. EGFR, PDGFR-α, and PDGFR-β gene expression was investigated by real-time polymerase chain reaction (qRT-PCR) on selected cases. "Hot-spot" mutations were screened for on EGFR, c-KIT, PDGFR-α, and PDGFR-β genes, by sequencing. All analysis was executed from formalin-fixed, paraffin-embedded specimens. Immunohistochemical overexpression of 2 or more tyrosine kinase receptors was observed in 18 of 28 tumors (64%), whereas only 5 tumors were consistently negative. Gene expression profiles were concordant with immunohistochemical overexpression in only 1 tumor, which displayed both high mRNA levels and specific immunoreactivity for PDGFR-α, and PDGFR-β. No activating mutations were found on the tumors included in the study. This study confirms that TKRs expression is frequently observed in ESS. Considering that the responsiveness to tyrosine kinase inhibitors is known to be related to the presence of specific activating mutations or gene over-expression, which are not detectable in ESS, TKRs immunohistochemical over-expression alone should not be considered as a reliable marker for targeted therapies in ESS. Specific post-translational abnormalities, responsible for activation of TKRs, should be further investigated.

Endometrial stromal tumors: immunohistochemical and molecular analysis of potential targets of tyrosine kinase inhibitors

BACKGROUND

The systemic treatment of malignant endometrial stromal tumors (EST) is not well established. A few reports describe objective responses to imatinib, which suggest a novel therapeutic strategy for these tumors. Due to these facts, we aimed to perform a retrospective analysis of possible molecular targets of tyrosine kinase inhibitors (TKI) in EST: KIT, PDGFRA and EGFR.

METHODS

52 endometrial stromal sarcomas and 13 undifferentiated endometrial sarcomas were examined and reviewed. Mutational analysis were performed for exons 9, 11, 13, and 17 of the KIT gene, exons 12 and 18 of the PDGFRA gene and exons 18, 19, 20 and 21 of the EGFR gene. The incidence and distribution of the KIT, PDGFRA, and EGFR expression were examined by immunohistochemistry, and EGFR amplification was assessed by fluorescence in situ hybridization.

RESULTS

No mutations in KIT, PDGFRA and EGFR genes were detected. Overexpression of KIT, PDGFRA, EGFR, was detected in 2 (3%), 23 (35.4%), 7 (10.8%) cases respectively, whereas amplification of EGFR gene was not found.

CONCLUSIONS

Absence of significant expression, amplification and activating mutations on these tyrosine kinase receptors suggest that it is unlikely that EST can benefit from therapies such as TKI on the systemic setting.

Uterine leiomyosarcoma management, outcome, and associated molecular biomarkers: a single institution's experience

BACKGROUND

Uterine leiomyosarcoma (ULMS) is an aggressive, rapidly progressive tumor lacking clinical and molecular predictors of outcome.

METHODS

ULMS patients (n = 349) were classified by disease status at presentation to MDACC as having intra-abdominal (n = 157) or distant metastatic disease (n = 192). Patient, tumor, treatment, and outcome variables were retrospectively retrieved. Formalin-fixed, paraffin-embedded tumor and control tissues from these patients (n = 109) were assembled in a tissue microarray and evaluated for hormone receptors and markers of angiogenesis, cell-cycle progression and survival. Patient, tumor, and treatment variables were correlatively analyzed.

RESULTS

The 5- and 10-year disease-specific survival (DSS) for the cohort was 42 and 27 %, respectively. Patients with primary intra-abdominal tumors had better outcomes than those with recurrent intraperitoneal tumors. Whites had a more favorable prognosis. In patients with intra-abdominal tumors, only mitotic count >10M/10HPF portended poorer prognosis. Patients with pulmonary metastasis had improved outcomes with "curative" metastasectomy. ULMS samples exhibited loss of ER and PR expression, overexpressed Ki-67, and altered p53, Rb, p16, cytoplasmic β-catenin, EGFR, PDGFR-α, PDGFR-β, and AXL levels. Metastatic tumors had increased VEGF, Ki-67, and survivin expression versus localized disease. Survivin and β-catenin expression were associated with intraperitoneal recurrence; high bcl-2 expression predicted longer DSS.

CONCLUSIONS

Analysis of both clinicopathologic factors and immunohistochemical biomarkers in ULMS identified several prognostic clinical and molecular factors, suggesting that further study may lead to improved ULMS understanding and treatment.

DOG1 immunoreactivity in uterine leiomyosarcomas

AIMS

DOG1 is a recently described marker of gastrointestinal stromal tumour (GIST) which is considered to be extremely sensitive and, among mesenchymal neoplasms, quite specific for this tumour type. Following the identification of DOG1 immunoreactivity in a uterine leiomyosarcoma, we wished to ascertain how prevalent DOG1 immunoreactivity was in this tumour type.

METHODS

We stained a series of uterine leiomyosarcomas (n=26) with DOG1 and with CD117 (c-kit), another marker of GIST. Staining with both markers was classified as negative, focal (<50% tumour cells positive) or diffuse (≥50% tumour cells positive).

RESULTS

DOG1 immunoreactivity was present in seven of 26 (27%) leiomyosarcomas. Staining was focal in five cases and diffuse in two. CD117 was positive in three of 26 (11.5%) cases, two focal and one diffuse. Two cases were positive with DOG1 and CD117. One of five uterine leiomyomas was focally positive with DOG1, and one extrauterine pelvic leiomyoma was diffusely positive with this marker.

CONCLUSIONS

Since GISTs have rarely been described as primary uterine neoplasms, the presence of DOG1 immunoreactivity in a uterine leiomyosarcoma may result in diagnostic confusion, and a panel of markers is necessary for diagnosis. Uterine leiomyosarcomas should be added to the list of mesenchymal neoplasms which may be DOG1 positive.

Involvement of proteasome β1i subunit, LMP2, on development of uterin leiomyosarcma

Background:

Although the majority of smooth muscle neoplasms found in the uterus are benign, uterine leiomyosarcoma is extremely malignant, with high rates of recurrence and metastasis. The development of gynecologic tumors is often correlated with secretion of female hormone; however, the development of human uterine leiomyosarcoma is not substantially correlated with hormonal conditions, and the risk factors are unclearly understood. Importantly, a diagnostic-biomarker, which distinguishes malignant human uterine leiomyosarcoma from benign tumor leiomyoma is yet to be established.

Aims:

It is necessary to analyze risk factors associated with human uterine leiomyosarcoma, in order to establish a diagnostic-biomarker and a clinical treatment method.

Patients and Methods:

Histology and Immunofluorescence Staining: Uteri obtained from LMP2^–/– mice or its parental mice (C57BL/6 mice) were fixed in 10% buffered formalin, incubated in 4% paraformaldehyde for 8 hours, and embedded in paraffin. Tissue sections (5 μm) were prepared and stained with H&E for routine histological examination or were processed further for immunofluorescence staining with appropriate antidodies. Furthermore, a total of 101 patients between 32 and 83 years of age and diagnosed as having smooth muscle tumors of the uterus were selected from pathological files. Immunohistochemistry staining for LMP2 was performed on serial human uterine leiomyosarcoma, leiomyoma and myometrium sections.

Results:

Homozygous deficient mice for a proteasome β1i subunit, LMP2 spontaneously develop uterine leiomyosarcoma, with a disease prevalence of ~40% by 14 months of age. Defective LMP2 expression in human uterine leiomyosarcoma was demonstrated, but present in human leiomyoma and myometrium.

Conclusions:

Loss in LMP2 expression may be one of the risk factors for human uterine leiomyosarcoma. LMP2 may be a potential diagnostic-biomarker and targeted-molecule for a new therapeutic approach.

Potential role of LMP2 as an anti-oncogenic factor in human uterine leiomyosarcoma: morphological significance of calponin h1

Uterine leiomyosarcoma (LMS) is a highly metastatic smooth muscle neoplasm for which calponin h1 is suspected to have a biological role as a tumor-suppressor. We earlier reported that LMP2-null mice spontaneously develop uterine LMS through malignant transformation of the myometrium, thus implicating this protein as an anti-tumorigenic candidate as well. In the present study, we show that LMP2 may negatively regulate LMS independently of its role in the proteasome. Moreover, several lines of evidence indicate that although calponin h1 does not directly influence tumorigenesis, it clearly affects LMP2-induced cellular morphological changes. Modulation of LMP2 may lead to new therapeutic approaches in human uterine LMS.

c-Kit proto-oncogene expression in endometrial hyperplasia and endometrial cancer

PURPOSE

To evaluate the expression of c-kit (CD117) in endometrial hyperplasia and endometrial cancer.

METHODS

Expression of c-kit in 10 normal endometrium, 18 simple endometrial hyperplasia, 16 complex endometrial hyperplasia (10 cases with atypia and 6 cases without atypia), and 6 endometrial cancer were investigated by immunohistochemistry.

RESULTS

c-Kit expression decreased as the lesion progressed to endometrial cancer. Immunostaining was mostly focal and weak in the normal endometrium and was mostly diffuse and strong in the simple and complex endometrial hyperplasia.

CONCLUSIONS

Simple and complex hyperplastic endometrial tissues express diffuse cytoplasmic staining for c-kit and the expression decreases with the progression of the lesion.

Potential role of LMP2 as tumor-suppressor defines new targets for uterine leiomyosarcoma therapy

Although the majority of smooth muscle neoplasms found in the uterus are benign, uterine leiomyosarcoma (LMS) is extremely malignant, with high rates of recurrence and metastasis. We earlier reported that mice with a homozygous deficiency for LMP2, an interferon (IFN)-γ-inducible factor, spontaneously develop uterine LMS. The IFN-γ pathway is important for control of tumor growth and invasion and has been implicated in several cancers. In this study, experiments with human and mouse uterine tissues revealed a defective LMP2 expression in human uterine LMS that was traced to the IFN-γ pathway and the specific effect of JAK-1 somatic mutations on the LMP2 transcriptional activation. Furthermore, analysis of a human uterine LMS cell line clarified the biological significance of LMP2 in malignant myometrium transformation and cell cycle, thus implicating LMP2 as an anti-tumorigenic candidate. This role of LMP2 as a tumor suppressor may lead to new therapeutic targets in human uterine LMS.

Uterine C-Kit positive low grade stromal sarcoma

Uterine C-Kit positive stromal tumors are rare, however, there are a few cases reported in literature. A 58-year-old post menopausal lady presented with bleeding per vaginum. An abdominal examination revealed an enlarged uterus. A computed tomography scan of the abdomen and pelvis showed a large myomatous uterus, with a probable subserosal intramural and intracavitary myoma or cervical myoma in the presence of a solitary large aortocaval node, with multiple bone lesions. The biopsy taken from the uterine mass had revealed, a low-grade uterine sarcoma, which was positive for CD117. This case is presented for its rarity and management dilemma.

Molecular Approach to Uterine Leiomyosarcoma: LMP2-Deficient Mice as an Animal Model of Spontaneous Uterine Leiomyosarcoma

Uterine leiomyosarcoma (LMS) develops more often in the muscle tissue layer of the uterine body than in the uterine cervix. The development of gynecologic tumors is often correlated with female hormone secretion; however, the development of uterine LMS is not substantially correlated with hormonal conditions, and the risk factors are not yet known. Importantly, a diagnostic-biomarker which distinguishes malignant LMS from benign tumor leiomyoma (LMA) is yet to be established. Accordingly, it is necessary to analyze risk factors associated with uterine LMS, in order to establish a treatment method. LMP2-deficient mice spontaneously develop uterine LMS, with a disease prevalence of ~40% by 14 months of age. We found LMP2 expression to be absent in human LMS, but present in human LMA. Therefore, defective LMP2 expression may be one of the risk factors for LMS. LMP2 is a potential diagnostic-biomarker for uterine LMS, and may be targeted-molecule for a new therapeutic approach.

Mice-lacking LMP2, immuno-proteasome subunit, as an animal model of spontaneous uterine leiomyosarcoma

Uterine tumors are the most common type of gynecologic neoplasm. Uterine leiomyosarcoma (LMS) is rare, accounting for 2% to 5% of tumors of the uterine body. Uterine LMS develops more often in the muscle tissue layer of the uterine body than in the uterine cervix. The development of gynecologic tumors is often correlated with female hormone secretion; however, the development of uterine LMS is not substantially correlated with hormonal conditions, and the risk factors are not yet known. Radiographic evaluation combined with PET/CT can be useless in the diagnosis and surveillance of uterine LMS. Importantly, a diagnostic biomarker, which distinguishes malignant LMS and benign tumor leiomyoma (LMA) is yet to be established. Accordingly, it is necessary to analyze risk factors associated with uterine LMS in order to establish a method of treatment. LMP2-deficient mice spontaneously develop uterine LMS, with a disease prevalence of ∼40% by 14 months of age. It is therefore of interest whether human uterine LMS shows a loss of LMP2 expression. We found LMP2 expression is absent in human LMS, but present in human LMA. Therefore, defective LMP2 expression may be one of the risk factors for LMS. LMP2 is potentially a diagnostic biomarker for uterine LMS, and gene therapy with LMP2-encording DNA may be a new therapeutic approach.

Reclassification of leiomyosarcoma as an extra-gastrointestinal stromal tumor of the gynecologic tract

Extra-gastrointestinal stromal tumors (EGISTs) are rare, and may have similar histologic appearance to leiomyosarcomas. Thus, these tumors are often misdiagnosed when occurring in gynecologic organs. We present the fourth case of EGIST occurring in the rectovaginal septum and a review of the literature. A 56-year-old woman presented with a rectovaginal mass that was initially diagnosed as leiomyosarcoma and was treated with resection and adjuvant radiation. She presented with recurrence 4 years later and underwent a second resection. After a 5-year disease-free interval, she experienced a second recurrence and after resection was diagnosed with recurrent EGIST. EGISTs are rare but should be considered in the differential diagnosis of spindle-cell neoplasms located in or near the gynecologic tract.

Genetic aberrations in soft tissue leiomyosarcoma

Leiomyosarcoma is a malignant mesenchymal tumor composed of cells showing smooth muscle differentiation. This tumor usually occurs in middle-aged or older adults, and forms a significant percentage of retroperitoneal, vascular, extremity, and uterine sarcomas. Leiomyosarcomas are most often associated with complex karyotypes with numerous chromosomal gains and losses. Some of these cytogenetic and molecular genetic aberrations correlate with histopathologic features and clinical outcomes. Identification of genetic alterations with specific identification of oncogenes and tumor suppressor genes may lead to additional insights into the tumorigenesis of leiomyosarcoma and the opportunity to confer the benefits of targeted therapy.

Molecular mechanisms of uterine leiomyosarcomas: involvement of defect in LMP2 expression

Patients with uterine leiomyosarcoma (LMS) typically present with vaginal bleeding, pain, and a pelvic mass. Typical presentations with hypercalcemia or eosinophilia have been reported. Radiographic evaluation with combined positron emission tomography/computed tomography may assist in the diagnosis and surveillance of women with uterine LMS. A recently developed risk-assessment index is highly predictive of disease-specific survival. Ovarian preservation does not appear to negatively impact outcome, and the addition of adjuvant therapy after surgical treatment does not seem to improve survival. It is noteworthy that LMP2-deficient mice exhibit spontaneous development of uterine LMS with a disease prevalence of ~37% by 12 months of age. The LMP2 gene is transcribed from a promoter containing an interferon (IFN)-γ-response factor element; thus, the IFN-γ-signal strongly induces LMP2 expression. Furthermore, a recent report demonstrated the loss of ability to induce LMP2 expression, which is an interferon (IFN)-γ-inducible factor, in human uterine LMS tissues and cell lines. Analysis of human uterine LMS shows somatic mutations in the IFNγ signalling pathway, thus the loss of LMP2 induction is attributable to a defect in the earliest steps of the IFN-γ signalling pathway. The discovery of an impaired key cell-signalling pathway may provide new targets for diagnostic approaches and therapeutic intervention.

Uterine contractions depend on KIT-positive interstitial cells in the mouse: genetic and pharmacological evidence

In the gastrointestinal tract, interstitial cells of Cajal (ICCs) generate a pacemaker activity. They produce electric slow waves that trigger and coordinate gut smooth muscle contractions. Interstitial cells of Cajal's slender shape is revealed by KIT immunostaining. Based on several features, including KIT expression and KIT dependence, ICC-like cells were identified in nongastrointestinal tissues. Here, we investigated in the mouse whether uterine contractions depend on ICC-like cells' activity. By labeling KIT-expressing cells, we found putative ICC-like cells in the uterus, observed as KIT-positive interstitial, long spindle-shaped cells with fine branched cytoplasm processes, distributed in muscular layers and in subepithelial connective tissue. We then checked the potential KIT dependence of ex vivo contractile activity of the uterus by combining genetic and pharmacological approaches, using the Kit W-v hypomorphic mutation, and imatinib as a KIT noncompetitive inhibitor. We found a significant reduction in frequency of longitudinal uterine contractions in Kit W-v/Kit W-v compared with Kit+/+ mice, whereas amplitude was unaffected. There was no difference in frequency or amplitude of circular uterine contractions between Kit W-v/Kit W-v and Kit+/+ mice. Ex vivo treatment of Kit+/+ uterine horns with imatinib resulted in a dose-dependent reduction of the frequency and amplitude of longitudinal myometrial contractions. Amplitude and frequency of circular contractions were unaffected in presence of imatinib. These concurrent results suggest that longitudinal contractions of the uterus depend on a KIT signaling pathway of ICC-like cells. The existence of ICC-like cells in the myometrium may enhance our understanding of uterine spontaneous contractile activity and suggest new approaches for treatment of uterine contractility disorders.

Primary leiomyosarcoma of the thyroid gland

Primary leiomyosarcomas of the thyroid gland are rare. We present the case of a 65-year-old woman with a rapidly enlarging neck mass for 2 months. The preoperative differential diagnosis included medullary thyroid cancer, anaplastic thyroid cancer, and primary versus metastatic sarcoma. The patient underwent total thyroidectomy, bilateral central neck dissections, and cervical thymectomy; she is currently being treated with ifosfamide and adriamycin. We review the literature on leiomyosarcoma of the thyroid, including the differential diagnoses, pathology, and alternative treatment strategies, including surgery and adjuvant therapy.

Application of immunohistochemistry to gynecologic pathology

CONTEXT

A large variety of tumors and lesions arise in the female genital tract. Although the majority of these can be correctly recognized on routine hematoxylin-eosin-stained slides, occasional cases present a diagnostic challenge. Immunohistochemical stains are extremely useful in resolving many of these problematic cases. As the knowledge in this area is constantly expanding, it is useful to have this updated information in a review form for easy access.

OBJECTIVE

To present our current knowledge of immunohistochemistry of the lesions of the female genital tract in a readily accessible form.

DATA SOURCES

The review is based on previously published articles on this topic.

CONCLUSIONS

Immunohistochemical stains help in reaching a conclusive diagnosis in a variety of problematic lesions seen in gynecologic pathology. As in any other system, immunohistochemical findings need to be interpreted in light of the clinical history and morphologic findings.

Expression of cyclooxygenase-2, c-kit, progesterone and estrogen receptors in uterine smooth muscle tumors: differential diagnosis

We examined the expression pattern of cyclooxygenase-2 (COX-2) and c-kit in uterine smooth muscle neoplasms and tried to determine the role of these markers in differential diagnosis. Archival tissue from 64 patients with uterine smooth muscle neoplasms (20 leiomyomas (LMs), 22 atypical leiomyomas (ALMs), and 22 leiomyosarcomas (LMSs)) was immunostained with antibodies against estrogen (ER) and progesterone receptors (PR), COX-2 and c-kit. 7 of 20 LM cases and 5 of 22 ALM cases were immunopositive for COX-2, whereas none of the LMS cases stained immunopositive (p< or =0.05). 4 of 20 LM cases and 5 of 22 ALM cases were immunopositive for c-kit, whereas 15 of 22 LMS cases showed c-kit immunopositivity (p< or =0.05). In conclusion, very few LMs and ALMs show COX-2 immunopositivity. LMSs usually do not express COX-2. COX-2 expression in smooth muscle tumors is not a prominent feature. Therefore, COX-2 inhibitors may not be useful in LMS therapy. C-kit was significantly expressed in uterine LMSs.

The management of patients with uterine sarcoma: a debated clinical challenge

Uterine sarcomas include a heterogeneous group of rare tumours that usually have an aggressive clinical behaviour and a poor prognosis. Total abdominal hysterectomy and bilateral salpingo-oophorectomy represents the standard surgical treatment. Pelvic and/or para-aortic lymphadenectomy is indicated for carcinosarcoma, but not for leiomyosarcoma and undifferentiated endometrial sarcoma. Some recent data on low numbers of patients with low-grade endometrial stromal sarcoma appear to show an incidence of nodal involvement higher than previously expected, thus suggesting a role for lymphadenectomy in this malignancy. Carcinosarcoma also requires a comprehensive surgical peritoneal staging. Postoperative treatment of uterine sarcomas has been long debated. Adjuvant pelvic radiotherapy appears to improve local control without any significant impact on overall survival. There is little evidence in the literature supporting the use of adjuvant chemotherapy in any gynaecological sarcomas except for carcinosarcomas. However, uterine sarcomas have a high tendency to develop distant recurrences, and recent data on adjuvant chemotherapy in soft tissue sarcomas are promising. As for the drugs to be used, it is worth noting that in a Swiss study, the combination of ifosfamide (IFO) and doxorubicin (DOX) obtained similar response rates in advanced gynaecological sarcomas and in advanced soft tissue sarcomas of other sites. In our decision-making scheme for early-stage disease, patients with leiomyosarcoma or undifferentiated endometrial sarcoma should receive adjuvant doxorubicin/epidoxorubicin (EPIDX)+ifosfamide, and those with carcinosarcoma should be treated with adjuvant cisplatin (CDDP)-based chemotherapy. The same drug regimens are used for the treatment of advanced disease. Sequential pelvic radiotherapy following chemotherapy could be delivered to selected cases. Recurrent disease often requires the integration of different therapeutic modalities, but no curative option is currently available with the possible exception of surgery for lung metastases and hormone therapy with or without debulking surgery for recurrent low-grade endometrial stromal sarcoma. Patients should be encouraged to enter clinical trials designed to identify new active drugs for these malignancies.

C-kit protein expression in uterine and ovarian mesenchymal tumours

The protooncogene c-kit encoding transmembrane tyrosine kinase receptor protein plays an important role in the signal transduction pathway that regulates cellular growth and repair. Gene product KIT overexpression has been shown in a number of different neoplasms, particularly in mastocytosis and gastrointestinal stromal tumours (GIST). The morphologic similarity of uterine mesenchymal tumours and GIST, and the presence of KIT protein in normal uterine tissue, suggests that uterine sarcomas may have the same c-kit overexpression. The purpose of this study was to determine the overexpression of c-kit protein in uterine and ovarian sarcomas. Immunohistochemical staining using a polyclonal anti-c-kit antibody was performed on tissue blocks from 12 carsinosarcomas, 14 leiomyosarcomas, 8 endometrial stromal sarcomas, 2 adenosarcomas, 1 atypical leiomyoma, 1 leiomyoma with limited experience, and 10 leiomyomas. The slides were evaluated by a semiquantitative method. C-kit was positive in 10 of 12 (83%) carcinosarcomas, 10 of 14 (71%) leiomyosarcomas, 6 of 8 75(%) endometrial stromal sarcomas, 1 of 2 (50%) adenosarcomas, 1 leiomyoma with limited experience, and 1 of 10 (10%) leiomyomas. The uterine sarcomas express c-kit, like GISTs. It seems that KIT may have a significant role in the oncogenesis of mesenchymal tumours of the uterus and ovary.

Adult human sarcomas. II. Medical oncology

Human sarcoma cells can be killed by radio- and chemotherapy, but tumor cells acquiring resistance frequently kill the patient. A keen understanding of the intracellular course of oncogenic cascades leads to the discovery of small molecular inhibitors of the involved phosphorylated kinases. Targeted therapy complements chemotherapy. Oncogene silencing is feasible by small interfering RNA. The restoration of some of the mutated or deleted tumor-suppressor genes (p53, Rb, PTEN, hSNF, INK/ARF and WT) by demethylation or reacetylation of their histones has been accomplished. Genetically engineered or naturally oncolytic viruses selectively lyse tumors and leave healthy tissues intact. Adeno- or retroviral vectors deliver genes of immunological costimulators, tumor antigens, chemo- or cytokines and/or tumor-suppressor proteins into tumor (sarcoma) cells. Suicide gene delivery results in apoptosis induction. Genes of enzymes that target prodrugs as their substrates render tumor cells highly susceptible to chemotherapy, with the prodrug to be targeted intracellularly. It will be combinations of sophisticated surgical removal of the nonencapsulated and locally invasive primary sarcomas, advanced forms of radiotherapy to the involved sites and immunotherapy with sarcoma vaccines that will cure primary sarcomas. Adoptive immunotherapy with immune lymphocytes will be operational in metastatic disease only when populations of regulatory T cells are controlled. Targeted therapy with small molecular inhibitors of oncogene cascades, the driving forces of sarcoma cells, alteration of the tumor stroma from a supportive to a tumor-hostile environment, reactivation or replacement of wild-type tumor-suppressor genes, and radio-chemotherapy (with much reduced toxicity) will eventually accomplish the cure of metastatic sarcomas.

PDGFR-α as a potential therapeutic target in uterine sarcomas

OBJECTIVE

Uterine sarcomas are a heterogeneous group of tumors with a propensity for metastasis and resistance to conventional therapy. Recent success in the treatment of other solid tumors with the targeted tyrosine kinase inhibitor imatinib mesylate offers new avenues for investigation. The primary target of imatinib is c-kit, but the drug also inhibits PDGFR-alpha and PDGFR-beta. Given the lack of identified molecular targets in endometrial stromal sarcomas, leiomyosarcomas, and carcinosarcomas, the purpose of this study was to determine the protein expression of c-kit, PDGFR-alpha, and PDGFR-beta in these tumors as a preliminary step to determining their susceptibility to directed therapy. A secondary goal was to identify specific gene mutations that might be associated with activation of these proteins in uterine sarcomas.

METHODS

Archived tissue from 42 cases of uterine sarcomas was stained for c-kit, PDGFR-alpha, and PDGFR-beta using immunohistochemistry. Laser-capture microdissected samples of uterine carcinosarcomas, or homogeneous areas of leiomyosarcomas or endometrial stromal sarcomas, were subjected to genetic analysis of PDGFR-alpha exons 12 and 18.

RESULTS

The majority (38/42, 90%) of uterine sarcomas lacked c-kit expression and 90% (38/42) demonstrated negative or weak staining for PDGFR-beta. In contrast, 70% (30/42) of cases had strong staining for PDGFR-alpha in the tumor but not in normal myometrium or endometrium. Sequencing results revealed no mutations in exons 12 or 18 of PDGFR-alpha.

CONCLUSION

c-kit and PDGFR-beta are unlikely to represent primary treatment targets in uterine sarcomas. The strong expression of PDGFR-alpha in uterine sarcoma specimens suggests a role for this receptor in tumor development, although its potential as a therapeutic target requires further investigation.

Over-expression of c-kit in a primary leiomyosarcoma of the thyroid gland

Primary leiomyosarcoma of the thyroid gland is rare. In this paper, we report a case of high-grade leiomyosarcoma of the thyroid gland in a 43-year-old man. Lung metastasis was also noted in this patient. Despite of aggressive surgical treatment, the patient died of uncontrolled local recurrent disease 6 months after the initial operation. Immunohistochemical studies showed the tumor cells were positive for c-kit proto-oncogene product. Imatinib mesylate was used as a post-operative adjuvant treatment but the response was poor. The role of tyrosine kinase inhibitors on the treatment of thyroid leiomyosarcomas is still unclear because this is the first report of c-kit over-expression in such tumors. Nevertheless, our results show that c-kit over-expression might not be an indicator of good response to imatinib mesylate treatment in thyroid leiomyosarcomas.

Diagnostic value of markers M2A, OCT3/4, AP-2γ, PLAP and c-KIT in the detection of extragonadal seminomas

AIMS

To compare the suitability of new seminoma markers including transcription factors AP-2gamma, OCT3/4 and M2A for detection of metastatic and extragonadal seminomas with the two well-known markers c-KIT and PLAP.

MATERIALS AND METHODS

The immunohistochemical distribution of PLAP, c-KIT, M2A, AP-2gamma and OCT3/4 was examined in two pineal germinomas, 28 metastatic seminomas and 10 of their testicular primaries. Evaluation of specificity was achieved by additional tissue array studies on 75 malignancies other than germ cell tumours (GCT). Clinical data including serum PLAP were available in 18 patients.

RESULTS

Compared with other markers, significantly better staining results were observed with antibodies to M2A and AP-2gamma in all seminomatous GCT. In contrast, the staining pattern with antibodies to c-KIT, PLAP and OCT3/4 was variable or absent. The lowest specificity was obtained with c-KIT, which was expressed in a variety of non-GCT. The only M2A+ mesothelioma expressed no other seminoma markers. No correlation between serum PLAP level and tissue PLAP expression was found.

CONCLUSIONS

M2A and AP-2gamma are the most sensitive markers for seminoma metastases or primary extragonadal seminomas. Combination of these markers provides highly specific and clear results for detection of a seminomatous GCT.

Malignant Transformation of Myomas: Myth or Reality?

The possibility that a fibroid may actually be a smooth muscle tumor of uncertain malignant potential or a leiomyosarcoma often dictates the clinical management of rapidly growing fibroids. This article provides a clinicopathologic background regarding uterine leiomyosarcomas and answers common questions that obstetricians and gynecologists have about the management of rapidly growing fibroids and leiomyosarcoma. The clinician must be aware that the infrequent occurrence of uterine leiomyosarcomas makes it difficult to establish absolutely firm recommendations for the diagnosis and management of this disease, particularly with regard to fertility preservation. Nevertheless, this article addresses major issues that a clinician might face in the evaluation of a smooth muscle tumor of the uterus that clinically may be malignant.

KIT (CD117): a review on expression in normal and neoplastic tissues, and mutations and their clinicopathologic correlation

CD117 (KIT) is a type III receptor tyrosine kinase operating in cell signal transduction in several cell types. Normally KIT is activated (phosphorylated) by binding of its ligand, the stem cell factor. This leads to a phosphorylation cascade ultimately activating various transcription factors in different cell types. Such activation regulates apoptosis, cell differentiation, proliferation, chemotaxis, and cell adhesion. KIT-dependent cell types include mast cells, some hematopoietic stem cells, germ cells, melanocytes, and Cajal cells of the gastrointestinal tract, and neoplasms of these cells are examples of KIT-positive tumors. Other KIT-positive normal cells include epithelial cells in skin adnexa, breast, and subsets of cerebellar neurons. KIT positivity has been variably reported in sarcomas such as angiosarcoma, Ewing sarcoma, synovial sarcoma, leiomyosarcoma, and MFH; results of the last three are controversial. The variations in published data may result from incomplete specificity of some polyclonal antibodies, possibly contributed by too high dilutions. Also, KIT is expressed in pulmonary and other small cell carcinomas, adenoid cystic carcinoma, renal chromophobe carcinoma, thymic, and some ovarian and few breast carcinomas. A good KIT antibody reacts with known KIT positive cells, and smooth muscle cells and fibroblasts are negative. KIT deficiency due to hereditary nonsense/missense mutations leads to disruption of KIT-dependent functions such as erythropoiesis, skin pigmentation, fertility, and gastrointestinal motility. Conversely, pathologic activation of KIT through gain-of-function mutations leads to neoplasia of KIT-dependent and KIT-positive cell types at least in three different systems: mast cells/myeloid cells--mastocytosis/acute myeloid leukemia, germ cells--seminoma, and Cajal cells--gastrointestinal stromal tumors (GISTs). KIT tyrosine kinase inhibitors such as imatinib mesylate are the generally accepted treatment of metastatic GISTs, and their availability has prompted an active search for other treatment targets among KIT-positive tumors such as myeloid leukemias and small cell carcinoma of the lung, with variable and often nonconvincing results.

Expression of CD117 (c-kit) receptor in dysgerminoma of the ovary: diagnostic and therapeutic implications

The proto-oncogene c-kit encodes a tyrosine kinase receptor, c-kit (CD117), which has been implicated in the development of a number of human malignancies. While the preferential expression of this protein has been well documented in testicular seminomas, there is little data concerning its expression in dysgerminomas of the ovary. We examined the expression of c-kit in 30 cases of ovarian dysgerminomas using immunohistohemical staining with a polyclonal anti-CD117 antibody. Staining was graded in a semiquantitative manner as follows: negative (no staining), 1+(1-10% staining), 2+(10-29% staining), 3+(30-50% staining), or 4+ (>50% staining). Of the 30 cases examined, 26 (87%) demonstrated immunoreactivity for CD117. In total, 10 (33%) demonstrated 4+ staining; 9 (30%) demonstrated 3+staining; 3 (10%) demonstrated 2+staining; 4 (13%) demonstrated 1+staining; and 4 (13%) demonstrated no staining. In conclusion, CD117 immunoreactivity was detected in 87% of ovarian dysgerminomas, a finding that correlates with previously reported frequencies of CD117 expression in seminomas (78-100%). Thus, antibodies to c-kit may be a useful diagnostic marker for ovarian dysgerminoma. Although the prognosis of patients with dysgerminoma is generally good, this receptor could potentially serve as a target for site-specific immunotherapy as an alternative and/or complement to conventional treatment options.

Clinical update of smooth muscle tumors of the uterus

Smooth muscle tumors of the uterus represent a spectrum of diseases that range from benign leiomyoma to malignant leiomyosarcoma. The leiomyoma is the most common of these neoplasms. Clinically, it is important to fully understand the differences in clinical presentation, biologic behavior, and management for patients with benign leiomyoma, smooth muscle tumors of uncertain malignant potential, and leiomyosarcoma. The goal of this review is to present the most recent information about common smooth muscle tumors of the uterus including their etiology, histopathology, radiographic and clinical presentations, and available treatment options.

Gastrointestinal stromal tumors metastatic to the ovary: a report of five cases

Five cases of gastrointestinal stromal tumor metastatic to the ovary are reported. The average patient age was 59 years (range, 44-81 years). The primary tumor was in the small bowel or its mesentery (4 cases) or stomach (1 case). The primary and metastatic tumors were discovered synchronously in 3 cases. In the other 2 cases, the ovarian tumors were discovered 18 months before a gastric tumor was identified and 27 years after a small bowel tumor had been resected. The ovarian tumors (three of which were bilateral) were usually solid, tan, and lobulated. Microscopically, three tumors had a pure spindle cell morphology, and two both spindle and epithelioid cell components. The diagnosis in all 5 cases was confirmed with positive c-kit (CD117) and negative desmin immunostaining. Variably positive immunoreactivity for either or both h-caldesmon and smooth muscle actin was seen in all 5 cases, and 3 cases were CD34-positive. Four patients died between 1 and 6.5 years (mean, 2.8 years) from the time of ovarian tumor diagnosis. The main differential diagnostic consideration was leiomyosarcoma; the most important features to help exclude this diagnosis were an absence of tumor in the uterus, low histologic grade, and a desmin-negative, c-kit-positive immunophenotype. Other differential considerations, including endometrial stromal sarcoma and fibrosarcoma, are discussed. Most of the ovarian tumors in this series were initially diagnosed as tumors of other types, a misdiagnosis with significant therapeutic and prognostic implications because of the specific therapy now available for gastrointestinal stromal tumors.

Imatinib Mesylate (Gleevec)-Targeted Kinases Are Expressed in Uterine Sarcomas

The purpose of this study was to determine whether 3 tyrosine kinases known to be inhibited by imatinib mesylate are expressed in a variety of uterine sarcomas. The authors assessed c-kit, abl, and platelet-derived growth factor receptor-beta (PDGFR-beta) expression in 8 endometrial stromal sarcomas (ESSs), 5 leiomyosarcomas (LMSs), 4 high-grade endometrial sarcomas (HGESs), and 21 malignant mixed mullerian tumors (MMMTs). Tissue sections were stained with commercially available antibodies for c-kit, abl, and PDGFR-beta. Staining intensity was described as 0 (no staining), +1 (weak), +2 (moderate), and +3 (strong). Positive staining was defined as moderate to strong if found in more than 10% of tumor cells. Expression of c-kit ranged from 0% in LMSs to 25% in HGESs. Protein expression of abl was more significant, ranging from 25% in LMSs and ESSs to 43% in MMMTs. Only 1 LMS sample stained focally for abl (+1). Abl expression was observed in only the carcinomatous elements of the MMMTs, with diffuse staining in the cytoplasm and nucleus. In most, the staining intensity was +2. All tumors stained positive for PDGFR-beta. MMMT samples showed PDGFR-beta expression in both the carcinomatous and sarcomatous portions. In all samples, staining for PDGFR-beta was concentrated at the cell membrane and diffusely in the cytoplasm. These results indicate that many uterine sarcomas express 1 or more of the kinases targeted by imatinib mesylate and that further investigation of imatinib as a therapy for uterine sarcomas is warranted.

Expression of c-kit in uterine carcinosarcoma

OBJECTIVES

The use of tyrosine kinase inhibitors (TKIs) has resulted in successful treatment of KIT-positive neoplasms. Carcinosarcoma is a very aggressive neoplasm. Consequently, c-kit expression may have significant clinical implications for this tumor. The purpose of the present study was to assess c-kit expression in the carcinomatous and sarcomatous element of carcinosarcoma to identify if KIT represents a therapeutic target for treatment of this neoplasm.

METHODS

Immunohistochemical staining for c-KIT was performed on paraffin-embedded tissue blocks of 20 consecutive uterine specimens with carcinosarcoma, 40 with endometrial carcinoma, and 12 with atrophic endometrium. Two pathologists assessed the scoring index of staining.

RESULTS

In the stromal element of carcinosarcoma, no immunohistochemically c-KIT stained cells were observed and in the epithelial element, a low scoring index of staining was present. In endometrial endometrioid carcinoma, the scoring index was high in only 15% of the specimens. In the atrophic endometrium, a low scoring index was seen in all specimens.

CONCLUSIONS

Our results seem to suggest that c-kit probably plays no major role in the pathogenesis of the majority of these tumors while it may be involved in the pathogenesis of some endometrial carcinomas. In view of the multiple molecular targets that are activated by imatinib mesylate, no definitive conclusions can be drawn with regard its effectiveness in carcinosarcomas based on the present study. Further studies of c-kit expression in larger series of carcinosarcomas in order to settle the controversial issues with regard to frequency of expression, prognostic, and clinical value are warranted.

Treatment and recurrence patterns in endometrial stromal sarcomas and the relation to c-kit expression

INTRODUCTION

Endometrial stromal sarcomas (ESS) are a rare gynecologic malignancy. The optimal management of this cancer remains unclear, although previous reports have failed to demonstrate a clear benefit to adjuvant chemotherapy or radiation. With the successful application of directed biological therapy in other sarcomas, a review of the behavior and biology of this disease is warranted.

OBJECTIVES

To review outcomes and patterns of failure in patients with endometrial stromal sarcoma diagnosed over 31 years at our institution and the relationship to protooncogene c-kit expression.

MATERIALS AND METHODS

Hospital records and pathology were reviewed for 28 patients with endometrial stromal sarcomas [19 low-grade (LGESS) and 9 high-grade (HGESS)] treated between 1972 and 2003. Archival tissue samples from 16 patients were available and stained with CD 117 (c-kit) antibody (1:25 dilution). Staining intensity was graded 1+ to 3+ and distribution of the cellular staining as focal (10-30% of the cells), intermediate (30-60% of the cells), or diffuse (>60% of the cells). Positive tumors had more than 10% of cells comprising the neoplasm display immunoreactivity. RESULTS.: We found a significant difference in 5-year overall survival between LGESS and HGESS (P = 0.001). There was no significant difference in overall survival for patients with local versus advanced disease (P = 0.53) or in overall survival for those who underwent lymphadenectomy and those who did not (P = 0.92). 50% of patients received postoperative radiation with no difference in disease-free or overall survival (P = 0.68 and P = 0.53). Ten patients relapsed (36%, four HGESS and six LGESS). Seven of sixteen (43.8%) tumor samples expressed detectable c-kit. Five of seven (71%) were HGESS, and the other two (22%) were LGESS tumors. The median survival of patients with c-kit-positive versus c-kit-negative tumors was 12 and 47 months, respectively.

CONCLUSIONS

This study confirms the superior overall prognosis of LGESS relative to HGESS, despite the similar rates of relapse. Although hard to assess, due to population heterogeneity and small numbers, adjuvant chemotherapy and radiation appear to be of limited benefit. Expression of c-kit was common, especially in high-grade lesions and may represent a potential therapeutic target.

Smooth Muscle Tumors of the Ovary

We studied 54 ovarian smooth muscle tumors with an emphasis on histologic criteria for malignancy. Twenty-two leiomyomas were identified, including 7 typical, 11 cellular, 2 mitotically active, 1 with bizarre nuclei, and 1 myxoid. Follow-up ranging from 12 to 240 months (mean, 77.6 months) was available for 14 patients; all were alive with no evidence of disease. Of 26 leiomyosarcomas, including 2 myxoid leiomyosarcomas, most were readily diagnosed by the presence of at least two of the following: moderate or severe cytologic atypia, mitotic rate > or =10 mitotic figures per 10 high power fields, and tumor cell necrosis. Some cytologically atypical tumors demonstrated lesser mitotic activity of 5 to 9 mitotic figures per 10 high power fields, in the absence of tumor cell necrosis. Sixty percent of these were clinically malignant, supporting a diagnosis of leiomyosarcoma in such tumors. Follow-up was available for 21 patients. Seventy-one percent developed recurrent disease at a mean of 19 months, and 62% died of their disease at a mean of 24 months. Four tumors were deemed of uncertain malignant potential, and two that were stage II both recurred in the pelvis. One case of ovarian intravenous leiomyomatosis had a benign outcome at 42 months, as did one case of ovarian leiomyoma with leiomyomatosis peritonealis disseminata at 180 months. Overall, ovarian smooth muscle tumors encompass the same varied histologic spectrum as their uterine counterparts. The main tumors in the differential diagnosis are those in the fibroma/thecoma category, spindle cell carcinomas, and metastatic gastrointestinal stromal tumors.

Vimentin-positive, c-kit-negative interstitial cells in human and rat uterus: a role in pacemaking?

The mechanism underlying spontaneous pacemaker potential in the uterus is not clearly understood. Several spontaneously active smooth muscles have interstitial cells of Cajal (ICCs) or ICC-like cells. We therefore examined cells from freshly dispersed uterine muscle strips (from pregnant human and rat myometrium) and in situ uterine preparations to determine the cell types present. Both preparations revealed numerous ICC-like cells; they were multipolar, with spider-like projections and enlarged central regions. These cells were readily distinguished from uterine myocytes by their morphology and ultrastructure, i.e., no myofilaments, numerous mitochondria, caveolae, and filaments. In addition, the ICC-like cells were noncontractile. These cells were negative to c-kit, a classic marker for ICCs. They stained positive for the intermediate filament, vimentin, a marker for cells of mesenchymal origin but not differentiated myocytes. The ICC-like cells had a more or less stable resting membrane potential of -58+/-7 mV compared with smooth-muscle cells, -65+/-13 mV, and produced outward current in response to voltage clamp pulses. However, in contrast with uterine myocytes, inward currents were not observed. This is the first description of ICC-like cells in myometrium and their role in the uterus is discussed, as possible inhibitors of intrinsic smooth-muscle activity.

Uterine leiomyosarcoma: present management

PURPOSE OF REVIEW

To review current investigations impacting management of uterine leiomyosarcoma (LMS).

RECENT FINDINGS

Patients with uterine LMS typically present with vaginal bleeding, pain, and a pelvic mass. Atypical presentations with hypercalcemia or eosinophilia have been reported. Radiographic evaluation with combined positron emission tomography/computed tomography may assist in diagnosis and surveillance in women with uterine LMS. Stage and tumor grade continue to appear to be valid prognostic indicators. A recently developed risk-assessment index is highly predictive of disease-specific survival. Ovarian preservation does not appear to negatively impact outcome. The addition of adjuvant therapy after surgical management does not seem to improve survival. Novel therapies may result from continued improvements in our knowledge of the molecular biology of uterine LMS.

SUMMARY

Despite the infrequency of uterine LMS, several recent investigations have advanced our understanding of the disease.