PTEN mutations in uterine sarcomas

Differences in gynecologic tumor development in Amhr2-Cre mice with KRASG12D or KRASG12V mutations

How different KRAS variants impact tumor initiation and progression in vivo has not been thoroughly examined. We hypothesize that the ability of either KRAS^G12D or KRAS^G12V mutations to initiate tumor formation is context dependent. Amhr2-Cre mice express Cre recombinase in tissues that develop into the fallopian tubes, uterus, and ovaries. We used these mice to conditionally express either the KRAS^G12V/+or KRAS^G12D/+ mutation. Mice with the genotype Amhr2-Cre Pten^(fl/fl) Kras^G12D/+(G12D mice) had abnormal follicle structures and developed low-grade serous ovarian carcinomas with 100% penetrance within 18 weeks. In contrast, mice with the genotype Amhr2-Cre Pten^(fl/fl) Kras^G12V/+ (G12V mice) had normal follicle structures, and about 90% of them developed uterine tumors with diverse histological features resembling those of leiomyoma and leiomyosarcoma. Granulosa cell tumors also developed in G12V mice. Differences in cell-signaling pathways in the uterine tissues of G12D and G12V mice were identified using RNA sequencing and reverse-phase protein array analyses. We found that CTNNB1, IL1A, IL1B, TNF, TGFB1, APP, and IL6 had the higher activity in G12V mice than in G12D mice. These mouse models will be useful for studying the differences in signaling pathways driven by Kras^G12V/+ or Kras^G12D/+ mutations to aid development of targeted therapies for specific KRAS mutant variants. Our leiomyoma model driven by the Kras^G12V/+ mutation will also be useful in deciphering the malignant progression from leiomyoma to leiomyosarcoma.

Genomics of gynaecological carcinosarcomas and future treatment options

Gynaecological carcinosarcomas are the most lethal gynaecological malignancies that are often highly resistant to standard chemotherapy. They are composed of both carcinomatous and sarcomatous components and are associated with high rates of metastatic disease. Due to their rarity, molecular studies have been carried out on relatively few tumours, revealing a broad spectrum of heterogeneity. In this review, we have collated the gene mutations, gene expression, epigenetic regulation and protein expression reported by a number of studies on gynaecological carcinosarcomas. Based on these results, we describe potential therapeutics that may demonstrate efficacy and present any pre-clinical studies that have been carried out. We also describe the pre-clinical models currently available for future research to assess the potential of molecularly matched therapies. Interestingly, over-expression of many biomarkers in carcinosarcoma tumours often doesn't correlate with a worse prognosis. Therefore, we propose that profiling the mutational landscape, gene expression, and gene amplification/deletion may better indicate potential treatment strategies and predict response, thus improving outcomes for women with this rare, aggressive disease.

Soft Tissue Sarcoma Cancer Stem Cells: An Overview

Soft tissue sarcomas (STSs) are an uncommon group of solid tumors that can arise throughout the human lifespan. Despite their commonality as non-bony cancers that develop from mesenchymal cell precursors, they are heterogeneous in their genetic profiles, histology, and clinical features. This has made it difficult to identify a single target or therapy specific to STSs. And while there is no one cell of origin ascribed to all STSs, the cancer stem cell (CSC) principle—that a subpopulation of tumor cells possesses stem cell-like properties underlying tumor initiation, therapeutic resistance, disease recurrence, and metastasis—predicts that ultimately it should be possible to identify a feature common to all STSs that could function as a therapeutic Achilles' heel. Here we review the published evidence for CSCs in each of the most common STSs, then focus on the methods used to study CSCs, the developmental signaling pathways usurped by CSCs, and the epigenetic alterations critical for CSC identity that may be useful for further study of STS biology. We conclude with discussion of some challenges to the field and future directions.

Molecular Pathology: Predictive, Prognostic, and Diagnostic Markers in Uterine Tumors

This article focuses on the diagnostic, prognostic, and predictive molecular biomarkers in uterine malignancies, in the context of morphologic diagnoses. The histologic classification of endometrial carcinomas is reviewed first, followed by the description and molecular classification of endometrial epithelial malignancies in the context of histologic classification. Taken together, the molecular and histologic classifications help clinicians to approach troublesome areas encountered in clinical practice and evaluate the utility of molecular alterations in the diagnosis and subclassification of endometrial carcinomas. Putative prognostic markers are reviewed. The use of molecular alterations and surrogate immunohistochemistry as prognostic and predictive markers is also discussed.

Sarcoma of the Uterus. Guideline of the DGGG (S2k-Level, AWMF Registry No. 015/074, August 2015)

Purpose: Official guideline published and coordinated by the German Society of Gynecology and Obstetrics (DGGG). Due to their rarity and their heterogeneous histopathology uterine sarcomas remain challenging tumors to manage and need a multidisciplinary approach. To our knowledge so far there is no evidence-based guideline on the appropiate management of these heterogeneous tumors. Methods: This S2k-guideline is the work of an representative committee of experts from a variety of different professions who were commissioned by the DGGG to carry out a systematic literature review of uterine sarcoma. Members of the participating scientific societies developed a structured consensus in a formal procedure. Recommendations: 1. The incidence and histopathologic classification of uterine sarcoma. 2. The clinical manifestations, diagnosis and staging of uterine sarcoma. 3. The management of leiomyosarcoma. 4. The management of endometrial stromal sarcoma and undifferentiated uterine sarcoma. 5. The management of adenosarcoma as well as carcinosarcomas. 6. The management of morcellated uterine sarcoma.

The effect of age at exposure on the inactivating mechanisms and relative contributions of key tumor suppressor genes in radiation-induced mouse T-cell lymphomas

Children are considered more sensitive to radiation-induced cancer than adults, yet any differences in genomic alterations associated with age-at-exposure and their underlying mechanisms remain unclear. We assessed genome-wide DNA copy number and mutation of key tumor suppressor genes in T-cell lymphomas arising after weekly irradiation of female B6C3F1 mice with 1.2Gy X-rays for 4 consecutive weeks starting during infancy (1 week old), adolescence (4 weeks old) or as young adults (8 weeks old). Although T-cell lymphoma incidence was similar, loss of heterozygosity at Cdkn2a on chromosome 4 and at Ikaros on chromosome 11 was more frequent in the two older groups, while loss at the Pten locus on chromosome 19 was more frequent in the infant-irradiated group. Cdkn2a and Ikaros mutation/loss was a common feature of the young adult-irradiation group, with Ikaros frequently (50%) incurring multiple independent hits (including deletions and mutations) or suffering a single hit predicted to result in a dominant negative protein (such as those lacking exon 4, an isoform we have designated Ik12, which lacks two DNA binding zinc-finger domains). Conversely, Pten mutations were more frequent after early irradiation (60%) than after young adult-irradiation (30%). Homozygous Pten mutations occurred without DNA copy number change after irradiation starting in infancy, suggesting duplication of the mutated allele by chromosome mis-segregation or mitotic recombination. Our findings demonstrate that while deletions on chromosomes 4 and 11 affecting Cdkn2a and Ikaros are a prominent feature of young adult irradiation-induced T-cell lymphoma, tumors arising after irradiation from infancy suffer a second hit in Pten by mis-segregation or recombination. This is the first report showing an influence of age-at-exposure on genomic alterations of tumor suppressor genes and their relative involvement in radiation-induced T-cell lymphoma. These data are important for considering the risks associated with childhood exposure to radiation.

Genomic analyses of gynaecologic carcinosarcomas reveal frequent mutations in chromatin remodelling genes

Malignant mixed Müllerian tumours, also known as carcinosarcomas, are rare tumours of gynaecological origin. Here we perform whole-exome analyses of 22 tumours using massively parallel sequencing to determine the mutational landscape of this tumour type. On average, we identify 43 mutations per tumour, excluding four cases with a mutator phenotype that harboured inactivating mutations in mismatch repair genes. In addition to mutations in TP53 and KRAS, we identify genetic alterations in chromatin remodelling genes, ARID1A and ARID1B, in histone methyltransferase MLL3, in histone deacetylase modifier SPOP and in chromatin assembly factor BAZ1A, in nearly two thirds of cases. Alterations in genes with potential clinical utility are observed in more than three quarters of the cases and included members of the PI3-kinase and homologous DNA repair pathways. These findings highlight the importance of the dysregulation of chromatin remodelling in carcinosarcoma tumorigenesis and suggest new avenues for personalized therapy.

Malignant mixed Müllerian tumours are a rare and aggressive gynaecological cancer with poor 5-year survival rates. Here, the authors characterize the mutational landscape of carcinosarcomas and highlight the role of chromatin remodelling dysregulation in carcinosarcoma tumorigenesis.

Risk of subsequent malignant neoplasms in long-term hereditary retinoblastoma survivors after chemotherapy and radiotherapy

PURPOSE

Hereditary retinoblastoma (Rb) survivors have increased risk of subsequent malignant neoplasms (SMNs). Previous studies reported elevated radiotherapy (RT) -related SMN risks, but less is known about chemotherapy-related risks.

PATIENTS AND METHODS

In a long-term follow-up study of 906 5-year hereditary Rb survivors diagnosed from 1914 to 1996 and observed through 2009, treatment-related SMN risks were quantified using cumulative incidence analyses and multivariable Cox proportional hazards regression models with age as the underlying time scale.

RESULTS

Nearly 90% of Rb survivors were treated with RT, and almost 40% received alkylating agent (AA) -containing chemotherapy (predominantly triethylenemelamine). Median follow-up time to first SMN diagnosis was 26.3 years. Overall SMN risk was not significantly elevated among survivors receiving AA plus RT versus RT without chemotherapy (hazard ratio [HR], 1.27; 95% CI, 0.99 to 1.63). AA-related risks were significantly increased for subsequent bone tumors (HR, 1.60; 95% CI, 1.03 to 2.49) and leiomyosarcoma (HR, 2.67; 95% CI, 1.22 to 5.85) but not for melanoma (HR, 0.74; 95% CI, 0.36 to 1.55) or epithelial tumors (HR, 0.89; 95% CI, 0.48 to 1.64). Leiomyosarcoma risk was significantly increased for survivors who received AAs at age < 1 (HR, 5.17; 95% CI, 1.76 to 15.17) but not for those receiving AAs at age ≥ 1 year (HR, 1.75; 95% CI, 0.68 to 4.51). Development of leiomyosarcoma was significantly more common after AA plus RT versus RT (5.8% v 1.6% at age 40 years; P = .01).

CONCLUSION

This comprehensive quantification of SMN risk after chemotherapy and RT among hereditary Rb survivors also demonstrates an AA-related contribution to risk. Although triethylenemelamine is no longer prescribed, our findings warrant further follow-up to investigate potential SMN risks associated with current chemotherapies used for Rb.

The regulatory roles of phosphatases in cancer

The relevance of potentially reversible post-translational modifications required for controlling cellular processes in cancer is one of the most thriving arenas of cellular and molecular biology. Any alteration in the balanced equilibrium between kinases and phosphatases may result in development and progression of various diseases, including different types of cancer, though phosphatases are relatively under-studied. Loss of phosphatases such as PTEN (phosphatase and tensin homologue deleted on chromosome 10), a known tumour suppressor, across tumour types lends credence to the development of phosphatidylinositol 3-kinase inhibitors alongside the use of phosphatase expression as a biomarker, though phase 3 trial data are lacking. In this review, we give an updated report on phosphatase dysregulation linked to organ-specific malignancies.

[Uterine leiomyosarcoma: epidemiology, pathology, biology, diagnosis, prognosis and treatment]

Uterine leiomyosarcoma is a rare disease with a poor prognosis. The rarity of this tumor needs a specialized management in tertiary reference centers in order to provide patients with optimal diagnostic, prognostic and therapeutic care. The pathological diagnosis relies on the presence of three characteristics in proliferating smooth muscle cells: necrosis, cytologic atypia and mitosis. Despite progress in the knowledge of the biology of these tumors, no oncogenic driver has been found. Prognosis depends mainly on the age of the patient, race, FIGO stage, mitotic index and hormonal receptor expression in the tumor. Surgery is one of the cornerstones of management and cytotoxic chemotherapy is the mainstay of treatment in metastatic disease with a potential role in the adjuvant setting. In locally advanced or metastatic disease, prognosis is poor with a median overall survival of about 12 to 14 months despite a 30% response rate to polychemotherapy regimens. Anti-angiogenics and hormonal therapy have a role to play in the setting of metastatic disease. It is mandatory to include such patients in clinical trials aiming to improve the therapeutic management of these patients. Multimodal therapy can improve the prognosis of selected patients too.

microRNAs in uterine sarcomas and mixed epithelial-mesenchymal uterine tumors: a preliminary report

Uterine sarcomas and mixed epithelial–mesenchymal uterine tumors are a heterogeneous group of rare tumors for which there are very few diagnostic markers available. As aberrant microRNA (miRNA) expression patterns represent putative diagnostic cancer markers, we aimed to identify miRNA expression profiles of the major uterine sarcoma subtypes and mixed epithelial–mesenchymal tumors of the uterus. Eighty-eight miRNAs were assessed by quantitative RT-PCR in cancerous and non-cancerous tissue samples collected from 29 patients with endometrial sarcoma, leiomyosarcoma, and mixed epithelial–mesenchymal tumors. Tumor and control samples significantly (P < 0.05) differed in the expression of miR-23b, miR-1, let-7f, and let-7c in endometrial sarcomas, and miR-1, let-7c, miR-133b, let-7b, miR-143, let-7a, let-7d, let-7e, let-7g, miR-222, let-7i, and miR-214 in mixed epithelial–mesenchymal tumors. All the significantly changed miRNAs were down-regulated in the malignant tissues as compared to their normal counterparts. This may suggest their tumor suppressor role in these malignancies. No statistically significant changes in miRNA expression levels were found between leiomyosarcoma tumors and controls. The identified miRNAs warrant further studies as valuable candidate markers for the differential diagnosis of uterine sarcomas from benign uterine lesions and between uterine sarcoma subtypes.

Dual targeting of mTOR and aurora-A kinase for the treatment of uterine Leiomyosarcoma

PURPOSE

The significance of mTOR activation in uterine leiomyosarcoma (ULMS) and its potential as a therapeutic target were investigated. Furthermore, given that effective therapies likely require combination mTOR blockade with inhibition of other targets, coupled with recent observations suggesting that Aurora-A kinase (Aurk-A) deregulations commonly occur in ULMS, the preclinical impact of dually targeting both pathways was evaluated.

EXPERIMENTAL DESIGN

Immunohistochemical staining was used to evaluate expression of activated mTOR components in a large (>200 samples) ULMS tissue microarray. Effects of mTOR blockade (using rapamycin) and Aurk-A inhibition (using MLN8237) alone and in combination on human ULMS cell growth, cell-cycle progression, and apoptosis were assessed in cellular assays. Drug interactions were determined via combination index analyses. The antitumor effects of inhibitors alone or in combination were evaluated in vivo.

RESULTS

Enhanced mTOR activation was seen in human ULMS samples. Increased pS6RP and p4EBP1 expression correlated with disease progression; p4EBP1 was found to be an independent prognosticator of patient outcome. Rapamycin inhibited growth and cell-cycle progression of ULMS cell strains/lines in culture. However, only a cytostatic effect on tumor growth was found in vivo. Combining rapamycin with MLN8237 profoundly (and synergistically) abrogated ULMS cells' growth in culture; interestingly, these effects were seen only when MLN8237 was preadministered. This novel therapeutic combination and scheduling regimen resulted in marked tumor growth inhibition in vivo.

CONCLUSIONS

mTOR and Aurk-A pathways are commonly deregulated in ULMS. Preclinical data support further exploration of dual mTOR and Aurk-A therapeutic blockade for human ULMS.

Classification, molecular characterization, and the significance of pten alteration in leiomyosarcoma

Leiomyosarcoma is a malignant smooth muscle neoplasm with a complicated histopathologic classification scheme and marked differences in clinical behavior depending on the anatomic site of origin. Overlapping morphologic features of benign and borderline malignant smooth muscle neoplasms further complicate the diagnostic process. Likewise, deciphering the complex and heterogeneous patterns of genetic changes which occur in this cancer has been challenging. Preliminary studies suggest that reproducible molecular classification may be possible in the near future and new prognostic markers are emerging. Robust recapitulation of leiomyosarcoma in mice with conditional deletion of Pten in smooth muscle and the simultaneous discovery of a novel role for Pten in genomic stability provide a fresh perspective on the mechanism of leiomyosarcomagenesis and promise for therapeutic intervention.

Increased risk of secondary uterine leiomyosarcoma in hereditary retinoblastoma

OBJECTIVE

In the US, second non-ocular malignancies are the primary cause of death in retinoblastoma survivors with the germline RB1 mutation. Soft tissue sarcomas are one of the most likely malignancies to pose a risk to these patients, with leiomyosarcoma (LMS) being the most common subtype. As our cohort is followed for a longer period, we discover new second malignancy risks for these patients.

METHODS

We estimated the risk for uterine leiomyosarcoma (ULMS) in a cohort of 1854 patients with retinoblastoma who were diagnosed at two US institutions from 1914 through 1996. The standardized incidence ratio and excess absolute risk were calculated by comparison with population data from the Connecticut Tumor Registry or from National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) database. The cumulative risk at 50 years of age was also calculated.

RESULTS

Seven of 525 female hereditary retinoblastoma patients developed ULMS. Five of these patients were used in the risk analysis, resulting in an excess risk of 3.87 per 10,000 women. Among hereditary patients who developed ULMS the excess risk increases dramatically with age: to 20/10,000 for female hereditary retinoblastoma patients aged between 30 and 39 years, and to 27/10,000 for patients aged 40+ years.

CONCLUSION

There is a substantial excess risk of ULMS in female hereditary retinoblastoma patients. As more patients survive into their thirties, this number is likely to increase. These findings raise the question of early childbearing, screening and prophylactic measures in hereditary retinoblastoma patients: all issues that would benefit from confirmation from other retinoblastoma cohorts, to allow for better guided counsel of these patients.

Molecular markers and clinical behavior of uterine carcinosarcomas: focus on the epithelial tumor component

Carcinosarcomas (malignant mixed Müllerian tumors) of the uterus are rare and aggressive malignancies consisting of an epithelial (carcinoma) and a mesenchymal (sarcoma) tumor component and are considered as metaplastic endometrial carcinomas. This study evaluated molecular characteristics and clinical behavior of uterine carcinosarcomas to improve treatment regimens in the future. Immunohistochemical expression of estrogen receptor-α and -β, progesterone receptor-A and -B, MLH1, MSH2, MSH6, PTEN (phosphatase and tensin homolog deleted on chromosome 10), p53, β-catenin and cyclin D1 was determined in 40 uterine carcinosarcomas. Immunostaining was compared between epithelial and mesenchymal tumor components. To determine the prognostic role of the epithelial component, clinicopathological data and survival were compared between patients with endometrioid and non-endometrioid epithelial tumor components. To determine prognosis of carcinosarcomas compared with high-risk endometrial carcinomas, clinicopathological characteristics and survival were compared between these patients. Hormone receptor expression occurred infrequently: estrogen receptor-α (8%) and -β (32%), progesterone receptor-A (0%) and -B (23%), next to β-catenin (4%) and cyclin D1 (7%). PTEN, MLH1, MSH2 and MSH6 mutations occurred in 39%, 33%, 22% and 21%, respectively (based on absent immunostaining). Overexpression of p53 was observed in 38%. Expression patterns of p53, MSH2 and MSH6 corresponded between epithelial and mesenchymal tumor components. In our cohort, the epithelial component caused the majority of metastases (72%) and vascular invasion (70%). Survival tended to be worse for patients with a non-endometrioid epithelial component compared with an endometrioid epithelial component (5-year survival: 26% and 55%, respectively). Survival was worse for patients with uterine carcinosarcomas compared with high-risk endometrial carcinomas (grade 3 endometrioid and non-endometrioid); 5-year survival rates: 42%, 77% and 57%, respectively. Our results support the monoclonal origin of uterine carcinosarcomas. The epithelial component determines prognosis by causing the majority of metastases and vascular invasion. To improve prognosis, treatment should focus on the epithelial tumor component of uterine carcinosarcomas.

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.

Upregulation of Wilms’ tumour gene 1 (WT1) in uterine sarcomas

AIM

Overexpression of Wilms' tumour gene (WT1) has been proven in several tumours. Previous research of our group on the cell cycle of uterine leiomyosarcoma (LMS) and carcinosarcoma (CS) suggested a possible role for WT1. We therefore intended to further explore the expression pattern of WT1 in uterine sarcomas.

METHODS

27 CS, 38 LMS, 15 endometrial stromal sarcomas (ESS) and seven undifferentiated sarcomas (US) were collected. WT1 expression was evaluated by immunohistochemistry (IHC) in 87 samples, by RT-PCR (m-RNA expression) in 23 random selected samples and by Western blotting in 12 samples, separating cytoplasmic and nuclear proteins. A pilot study to detect mutations (exons 7-10) was performed on eight samples.

RESULTS

IHC showed WT1 positivity in 12/27 CS, 29/38 LMS, 7/15 ESS and 4/7 US. All-but-one sample had a positive RT-PCR. All Western blottings were positive with more cytoplasmic expression in 9/12 cases. No mutations were found.

CONCLUSIONS

WT1 is overexpressed in uterine sarcomas. Since increased levels of mRNA determine the biological role, WT1 might contribute to uterine sarcoma tumour biology.

Analysis of fumarate hydratase mutations in a population-based series of early onset uterine leiomyosarcoma patients

Germline mutations in fumarate hydratase (FH) gene at 1q43 predispose to hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome. In HLRCC, the most common clinical features are leiomyomas of the skin and uterus, and in a subset of the families, renal cell cancer (RCC) and uterine leiomyosarcoma (ULMS) occur frequently at young age. This study was conducted to evaluate the possible contribution of FH mutations in a population-based series of early onset (< or = 45 years) ULMSs. Eighty-one cases were identified through the national cancer registry, and samples from 67 cases (83%) were available for FH mutation screening and analysis of allelic imbalance (AI) at the FH locus. Seventeen percent of tumors showed AI. In the mutation analysis, a novel missense mutation K424R was found. The mutation was also found from the patient's normal tissue. To study whether this variant has functional consequences, FH enzyme activity assay was performed in a cell model. The activity of the mutated protein was significantly reduced as compared to wild type (p = 0.009). This study shows that FH germline mutations can occur in seemingly nonsyndromic cases of ULMS (1/67, 1.5%). It appears that on the population level hereditary FH defects do play a role in pathogenesis of sporadic early onset ULMSs, albeit rarely.

Loss of DNA copy number of 10q is associated with aggressive behavior of leiomyosarcomas: a comparative genomic hybridization study

Leiomyosarcomas (LMS) account for 10-20% of all soft tissue sarcomas. We analyzed 10 primary, 5 metastatic, and 2 recurrent extrauterine LMS. Genomic imbalances were detected in 15 out of the 17 tumors. The most common regions of loss were 13q (59%, 10 of 17), 10q (59%, 10 of 17), 2q (35%, 6 of 17), and 16q (29%, 5 of 17). The most common region of gain was 5p (35%, 6 of 17). High-level gain of DNA copy number was detected in 6p and 17p. Loss of function of tumor suppressor genes or the activation of oncogenes (or both of these factors) resulting from these copy number changes might play an important role in the development of extrauterine LMS. Large tumors and tumors with metastasis showed 10q deletions. Gain of 5p was detected only in G3 tumors. These findings are consistent with our earlier study on uterine LMS and indicate that loss of 10q and gain of 5p are associated with an aggressive behavior of LMS. A larger series of cases is needed to confirm these results.

Molecular analysis of primary and recurrent giant cell tumors of bone

The status of microsatellite markers located on chromosomes 1p36, 3p25, 5q23, 9p22, 10q23, 10q24, 17p13, and 19q12 was used to determine loss of heterozygosity (LOH) in primary giant cell tumors (GCT) of bone in 12 patients. The cases included primary, locally recurrent, and metastatic GCT; three tumors were classified as malignant GCT, based on their morphological features. Microdissection was performed on 24 paraffin-embedded tissue samples. An average of three separate topographic sites were microdissected from each tumor. Case selection in each instance was based on the availability of paired samples of tumor in primary GCTs and their corresponding recurrences, and the presence of normal tissue. The number of cases studied is too small for statistical studies, and thus the analysis is descriptive. All cases were informative for >80% of the markers used. Both primary GCTs and local recurrences and lung metastases displayed LOH of three or more markers, and intratumoral heterogeneity was frequent. Fractional allelic losses (FAL) were not different in recurrent and nonrecurrent GCT. FAL was greatest (>30%) in the metastatic group of GCT. Allelic losses of 1p, 9q, and 19q regions were frequent in all groups. LOH of 17p (in proximity to the p53 locus) and 9p occurred exclusively in the pulmonary metastases from GCT. LOH of 9q and 19q was present in primary as well as recurrent GCTs and in one malignant GCT. Involvement of 1p (including MYCL) and 9q regions has not been previously reported in GCT of bone. The pattern of LOH evident in the 17 markers used in the present study suggests that GCT with malignant features may follow an evolutionary pathway similar to the usual primary GCT of bone.

Prognostic importance of vascular endothelial growth factor and its receptors in the uterine sarcoma

Vascular endothelial growth factor (VEGF) and its receptors play an important role in tumor progression; however, there is no report regarding this factor in uterine sarcoma. Thirty-nine patients with uterine sarcoma, 14 carcinosarcomas, 4 endometrial stromal sarcomas, and 21 leiomyosarcomas, were studied. By immunohistochemical staining, VEGF was not detected in normal uterine smooth muscle, but VEGF receptor-1 (flt-1) and VEGF receptor-2 (flk-1) were observed in 14 and 4 of 14 normal smooth muscles, respectively. Of 39 sarcomas, 25 expressed VEGF, and 38 and 34 sarcomas expressed flt-1 and flk-1 at various intensities, respectively. The staining intensity of VEGF, flt-1, and flk-1 was significantly higher in sarcoma than in normal uterine smooth muscle, but that of phospho-flt-1 (p-flt-1) was significantly lower in sarcoma than in normal uterine smooth muscle. When sarcomas were divided into two groups according to staining intensity, a significant difference in survival curves was observed in only p-flt-1 of leiomyosarcoma (P= 0.008), and in all sarcomas, a lower survival curve was also observed in the high staining intensity group than in the low staining intensity group, although there was no significant difference (P= 0.102). In conclusion, VEGF and its receptors are suggested to be involved in progression of uterine sarcoma, but only the p-flt-1 level significantly affected the survival of leiomyosarcoma patients.

Differential Diagnosis of Smooth Muscle Tumors Utilizing p53, pTEN and Ki-67 Expression with Estrogen and Progesterone Receptors

BACKGROUND/AIM

To investigate the expression and value for diagnosis of the genes, p53 and pTEN, the protein, Ki-67, and the receptors, estrogen and progesterone, in differentiating smooth muscle tumors of the uterus.

MATERIAL AND METHOD

Seventeen samples of leiomyosarcoma, 2 smooth muscle tumors with uncertain malignant potential (STUMP), 9 atypical myomas and 15 leiomyomas were stained immunohistochemically. The chi(2) test was used for the statistical analysis of the data.

RESULTS

The malignant side of the spectrum was strongly stained for Ki-67 and p53 while uniformly decreasing toward the benign tumors. The results were found to be statistically significant (p < 0.0001). The staining for progesterone receptor was also statistically significant, but the tumors that were considered benign, such as leiomyoma and atypical myoma, were the ones strongly stained (p = 0.005). The expression of estrogen receptor was significant in these tumors, but the p value was very close to the cut-off value (p = 0.07). As the degree of differentiation of the tumor increased, the trend showed stronger staining for estrogen receptor. However, no difference was detected in the staining properties of the tumors for pTEN (p = 0.2457).

CONCLUSION

The expression of Ki-67, p53 and progesterone receptors is promising in immunodifferentiation of smooth muscle tumors of the uterus with malignant potential.

Estrogen and Progesterone Receptor Expression in Uterine and Extrauterine Leiomyosarcomas

The authors have noted anecdotal cases of extrauterine leiomyosarcomas (LMS) with estrogen receptor (ER) and progester-one receptor (PR) immunoreactivity. However, there are few studies that have compared ER and PR immunoexpression in LMS of uterine and extrauterine origin. The authors obtained a representative formalin-fixed, paraffin-embedded tissue block from cases of uterine LMS (n = 15) and extrauterine LMS (n = 16) from the archives of the Cleveland Clinic Foundation and performed immunohistochemical staining for ER and PR. Staining was evaluated by 2 observers in a semiquantitative manner using the following scale: 0, no nuclear staining; 1+, 1 to 25% of nuclei stained; 2+, 26 to 50% of nuclei stained; 3+, 51 to 75% of nuclei stained; 4+, 76 to 100% of nuclei stained. The majority of uterine LMS stained for ER (13 of 15, 87%), PR (12 of 15, 80%), or both ER and PR (12 of 15, 80%), with most cases showing 3+ or 4+ positive staining. For the extrauterine LMS cases, staining for ER was seen in 4 of 16 cases (25%), staining for PR was observed in 2 of 16 cases (13%), and staining for both ER and PR was seen in 2 of 16 cases (13%). One extrauterine LMS showed 4+ coexpression of ER and PR, but the remaining extrauterine cases showed only 1+ ER and/or PR immunoreactivity. These data suggest that most uterine LMS coexpress ER and PR, and most extrauterine LMS do not stain for these antigens. However, a subset of extrauterine LMS are ER and/or PR immunoreactive. This raises the possibility that hormonal manipulation may be beneficial in the treatment of these therapeutically recalcitrant tumors.

Role of PTEN in gastrointestinal stromal tumor progression

CONTEXT

Gastrointestinal stromal tumors (GISTs) are Kit/CD117-expressing mesenchymal neoplasms of uncertain malignant potential. The lack of a reliable method of prognostication hampers the selection of patients eligible for STI571 therapy. 10q22-q23 is a region involved in chromosomal losses found in a fraction of malignant primary and metastatic GISTs harboring PTEN (phosphatase and tensin homologue deleted on chromosome 10), a tumor suppressor gene often altered in human neoplasms.

OBJECTIVE

To investigate the role of PTEN in GISTs, an issue that to our knowledge has not been addressed previously.

DESIGN

PTEN status was determined in a series of 21 GISTs, with follow-up ranging between 6 and 198 months, using immunohistochemistry correlated with clinical data.

RESULTS

A greater than 25% fraction of cells with low or absent PTEN immunostaining was detected in 9 GISTs, including all those showing malignancy. By the log-rank test, a fraction of PTEN-deficient cells greater than 25% was associated with malignancy (P <.001). Percentage of cells underexpressing PTEN, size, cellularity, MIB-1 immunoreactivity, and coagulative necrosis proved to be associated with malignancy by Cox proportional hazards univariate analysis; low or absent expression of PTEN was the only factor selected by multivariate analysis (P =.03).

CONCLUSIONS

PTEN downregulation is implied in GIST progression. The immunohistochemical assessment of PTEN status appears to be a promising method of GIST prognostication.

Expression of PTEN encoding product in malignant lesions of gastric mucosa and its significance

AIM

To observe the expression of PTEN protein in gastric cancer and precancerous lesions, and to investigate the relationship between PTEN expression and the pathogenesis of gastric cancer.

METHODS

Normal gastric mucosa,chronic superficial gastritis, atrophic gastritis without intestinal metaplasia, atrophic gastritis with intestinal metaplasia, moderate and severe dysplasia, early and advanced gastric cancer, 60 cases each group, were selected for PTEN protein expression by SP immunohistochemistry.

RESULTS

The expression of PTEN encoding product in normal gastric mucosa was 100%. For chronic superficial gastritis, atrophic gastritis without intestinal metaplasia, atrophic gastritis with intestinal metaplasia, moderate dysplasia, severe dysplasia, the PTEN protein expression rate was 98.3%, 91.6%, 78.3%, 75%, 63.3%,respectively. The expression of PTEN protein in early stage and advanced gastric cancer was 61.7% and 43.3% respectively. Among the 120 cases of gastric cancer, 76 cases were intestinal type gastric cancer, the PTEN protein expression was 60.5%, 44 cases were diffuse gastric cancer , the PTEN protein expression was 38.6%.

CONCLUSION

The expression of PTEN protein is downregulated in the process of gastric cancer, PTEN protein can be used as a maker to evaluate the biological behaviours of gastric cancer.

PTEN/MMAC1 gene mutation is a rare event in soft tissue sarcomas without specific balanced translocations

The tumor suppressor gene PTEN/MMAC1 was identified on chromosome 10q23.3, which is homozygously deleted in many human malignancies. The loss of chromosome 10q was also frequently reported in some types of soft tissue sarcomas. Our study was designed to investigate the frequency of PTEN/MMAC1 gene mutation and to evaluate the role of the PTEN/MMAC1 gene in the tumorigenesis of soft tissue sarcomas without specific balanced translocations. We analyzed 51 cases of soft tissue sarcomas without specific balanced translocations for PTEN/MMAC1 mutations by polymerase chain reaction-single strand conformation polymorphism and direct sequencing. Mutations in the PTEN/MMAC1 gene were found in only 2 cases (3.9%). Both tumors with PTEN/MMAC1 mutation were leiomyosarcomas arising from the retroperitoneum and inferior vena cava, respectively. Two of 3 leiomyosarcomas arising from the intra-abdominal cavity examined harbored mutations of this tumor suppressor gene. This result suggests that leiomyosarcomas derived from the intra-abdominal cavity might have different tumorigenesis from those of an extremity or the trunk, from the viewpoint of PTEN/MMAC1 mutation, although PTEN/MMAC1 gene mutations are rare event in these soft tissue sarcomas.