Analysis of Ki-ras, p53, and MDM2 genes in uterine leiomyomas and leiomyosarcomas

An Unusual Endometrial Stromal Neoplasm With JAZF1-BCORL1 Rearrangement

Endometrial stromal tumors represent the second most common category of uterine mesenchymal tumors. Several different histologic variants and underlying genetic alterations have been recognized, one such being a group associated with BCORL1 rearrangements. They are usually high-grade endometrial stromal sarcomas, often associated with prominent myxoid background and aggressive behavior. Here, we report an unusual endometrial stromal neoplasm with JAZF1-BCORL1 rearrangement and briefly review the literature. The neoplasm formed a well-circumscribed uterine mass in a 50-yr-old woman and had an unusual morphologic appearance that did not warrant a high-grade categorization. It was characterized by a predominant population of epithelioid cells with clear to focally eosinophilic cytoplasm growing in interanastomosing cords and trabeculae set in a hyalinized stroma as well as nested and fascicular growths imparting focal resemblance to a uterine tumor resembling ovarian sex-cord tumor, PEComa, and a smooth muscle neoplasm. A minor storiform growth of spindle cells reminiscent of the fibroblastic variant of low-grade endometrial stromal sarcoma was also noted but conventional areas of low-grade endometrial stromal neoplasm were not identified. This case expands the spectrum of morphologic features seen in endometrial stromal tumors, especially when associated with a BCORL1 fusion and highlights the utility of immunohistochemical and molecular techniques in the diagnosis of these tumors, not all of which are high grade.

MDM2 for the practicing pathologist: a primer

The mouse double minute 2 (MDM2) gene is located on the long arm of chromosome 12 and is the primary negative regulator of p53. The MDM2 gene encodes an E3 ubiquitin-protein ligase that mediates the ubiquitination of p53, leading to its degradation. MDM2 enhances tumour formation by inactivating the p53 tumour suppressor protein. The MDM2 gene also has many p53-independent functions. Alterations of MDM2 may occur through various mechanisms and contribute to the pathogenesis of many human tumours and some non-neoplastic diseases. Detection of MDM2 amplification is used in the clinical practice setting to help diagnose multiple tumour types, including lipomatous neoplasms, low-grade osteosarcomas and intimal sarcoma, among others. It is generally a marker of adverse prognosis, and MDM2-targeted therapies are currently in clinical trials. This article provides a concise overview of the MDM2 gene and discusses practical diagnostic applications pertaining to human tumour biology.

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.

Endometrial stromal sarcomas with BCOR-rearrangement harbor MDM2 amplifications

Recently a novel subtype of endometrial stromal sarcoma (ESS) defined by recurrent genomic alterations involving BCOR has been described (HGESS‐BCOR). We identified a case of HGESS‐BCOR with a ZC3H7B‐BCOR gene fusion, which harbored an amplification of the MDM2 locus. This index case prompted us to investigate MDM2 amplification in four additional cases of HGESS‐BCOR. Tumors were analyzed for MDM2 amplification by array‐based profiling of copy number alterations (CNAs) and fluorescence in situ hybridization (FISH), as well as for MDM2 expression by immunohistochemistry (IHC). Additionally, a cohort of other mesenchymal uterine neoplasms, including 17 low‐grade ESS, 6 classical high‐grade ESS with YWHAE‐rearrangement, 16 uterine tumors resembling ovarian sex cord tumors, 7 uterine leiomyomas and 8 uterine leiomyosarcomas, was analyzed for CNAs in MDM2. Copy number profiling identified amplification of the 12q15 region involving the MDM2 locus in all five HGESS‐BCOR. Subsequent validation analyses of three tumors confirmed MDM2 amplification using MDM2 FISH. Accordingly, IHC showed MDM2 overexpression in all analyzed cases. None of the other uterine neoplasms in our series, including tumors that are in the histopathological differential diagnoses of HGESS‐BCOR, showed copy number gains of MDM2. Together, our results indicate that HGESS‐BCOR carries MDM2 amplifications, which has diagnostic implications and could potentially be used for targeted therapies in these clinically aggressive tumors.

Analysis of TP53 gene in uterine myomas: No mutations but P72R polymorphism is associated with myoma development

AIM

The aim of the present study was to investigate the familial and somatic mutations as well as polymorphisms of TP53 gene in patients with uterine leiomyoma.

METHODS

The study included 35 women with histologically diagnosed as uterine leiomyomas at the Gynecology Department of Adnan Menderes University Faculty of Medicine. Tissue and blood samples were analyzed for mutations and polymorphisms of TP53 gene by next generation sequencing (Miseq-Illumina). Acquired data was compared with the normal data in Ensembl database. Data from 1000 genome project and data from exome sequencing analyses in Intergen Genetic Diagnosis Center (Ankara) were used as controls for polymorphism analyses.

RESULTS

There were no mutations in tissue and blood samples. However, when the polymorphisms were evaluated, a significant difference was found in NM_000546.5(TP53):c.215C > G (p.Pro72Arg) polymorphism between the study and control groups. The results indicated that P72R/P72R genotype increased the risk of leiomyoma development by 6.3 fold (95% confidence interval [CI]: 2.880-13.793). There was a negative correlation between P72R/WT genotype and leiomyoma development (OR = 0.261, 95% CI: 0.114-0.596). P72R/P72R genotype was statistically higher in the patients with leiomyoma compared with the controls and 1000 genomes from Asian, European and World populations.

CONCLUSION

The results of the present study suggested that P72R/P72R genotype may be associated with development of uterine leiomyoma in the Turkish population in the Western part of the country.

Identification of key genes and pathways between type I and type II endometrial cancer using bioinformatics analysis

Endometrial carcinoma (EC) is a common malignant neoplasm of the female reproductive tract. The malignant degree of type II EC is much greater than that of type I EC, usually presenting with a high recurrence rate and a poor prognosis. Therefore, the present study aimed to examine the principal genes associated with the degree of differentiation in type I and type II EC and reveal their potential mechanisms. Differentially expressed genes (DEGs) were selected from the gene expression profiles derived from The Cancer Genome Atlas. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted. In the present study, the KEGG pathway enrichment analysis revealed that 5,962 upregulated DEGs were significantly enriched in the ‘p53 signaling pathway’ and involved in ‘lysine degradation’. In addition, 3,709 downregulated DEGs were enriched in ‘pathways in cancer’, as well as ‘tight junction regulation’, the ‘cell cycle’ and the ‘Wnt signaling pathway’. The 13 top hub genes MAPK1, PHLPP1, ESR1, MDM2, CDKN2A, CDKN1A, AURKA, BCL2L1, POLQ, PIK3R3, RHOQ, EIF4E and LATS2 were identified via the protein-protein interaction network. Furthermore, the OncoPrint algorithm from cBioPortal declared that 25% of EC cases carried genetic alterations. The altered DEGs (MAPK1, MDM2, AURKA, EIF4E and LATS2) may be involved in tumor differentiation and may be valuable diagnostic biomarkers. In conclusion, a number of principal genes were identified in the present study that may be determinants of poorly differentiated type II EC carcinogenesis, which may contribute to future research into potential molecular mechanisms. In addition, these genes may help identify candidate biomarkers and novel therapeutic targets for type II EC.

Identification of Differentially Expressed K-Ras Transcript Variants in Patients With Leiomyoma

PURPOSE

Molecular studies have demonstrated a wide range of gene expression variations in uterine leiomyoma. The rat sarcoma virus/rapidly accelerated fibrosarcoma/mitogen-activated protein kinase (RAS/RAF/MAPK) is the crucial cellular pathway in transmitting external signals into nucleus. Deregulation of this pathway contributes to excessive cell proliferation and tumorigenesis. The present study aims to investigate the expression profile of the K-Ras transcripts in tissue samples from patients with leiomyoma.

METHODS

The patients were leiomyoma cases who had no mutation in mediator complex subunit 12 ( MED12) gene. A quantitative approach has been applied to determine the difference in the expression of the 2 main K-Ras messenger RNA (mRNA) variants. The comparison between gene expression levels in leiomyoma and normal myometrium group was performed using relative expression software tool.

RESULTS

The expression of K-Ras4B gene was upregulated in leiomyoma group ( P = .016), suggesting the involvement of K-Ras4B in the disease pathogenesis. Pairwise comparison of the K-Ras4B expression between each leiomyoma tissue and its matched adjacent normal myometrium revealed gene upregulation in 68% of the cases. The expression of K-Ras4A mRNA was relatively upregulated in leiomyoma group ( P = .030). In addition, the mean expression of K-Ras4A gene in leiomyoma tissues relative to normal samples was 4.475 (95% confidence interval: 0.10-20.42; standard error: 0.53-12.67). In total, 58% of the cases showed more than 2-fold increase in K-Ras4A gene expression.

CONCLUSION

Our results demonstrated increased expression of both K-Ras mRNA splicing variants in leiomyoma tissue. However, the ultimate result of KRAS expression on leiomyoma development depends on the overall KRAS isoform balance and, consequently, on activated signaling pathways.

Malignant mesenchymal tumors of the uterus - time to advocate a genetic classification

INTRODUCTION

Sarcomas are rare uterine tumors with leiomyosarcomas and endometrial stromal sarcomas constituting the predominant entities often making their first appearance in young and middle-aged women. By histology combined with immunostaining alone some of these tumors can offer diagnostic challenges e.g. for the differential diagnosis between leiomyosarcomas and smooth muscle tumors of uncertain malignant potential (STUMP). Areas covered: Recent advances in the genetic classification and subclassification, respectively, have shown that genetic markers can offer a valuable adjunct to conventional diagnostic tools. Herein, we will review these recent data from the literature also referring to genetic alterations found in STUMP, endometrial stromal nodules, and leiomyomas including their variants. Expert commentary: For the future, we consider genetic classification as a necessary step in the clinical management of these tumors which will help not only to improve the diagnosis but also the therapy of these malignancies often associated with a worse prognosis.

Current Chemotherapy and Potential New Targets in Uterine Leiomyosarcoma

A variety of chemotherapeutic agents have been used for treating recurrent or advanced stage uterine leiomyosarcoma (ULMS). The response rates of these current agents are disappointing, with partial response rates varying from 0% to 33%, and complete response rates varying from 0% to 8%. Recent studies have documented many molecular changes in ULMSs. Prominent amongst these are gains of growth factors C-MYC, Bcl-2, K-ras, and Ki-67, and losses in tumor suppressors p16, p53, Rb1, ING2 and D14S267. Various techniques that have been used to target these molecules are presented. Targeting specific therapies at these underlying molecular changes could potentially yield better response rates with fewer side effects.

Association of XRCC1 Arg399GIn and Tp53 Arg72Pro polymorphisms and increased risk of uterine leiomyoma - A case-control study

The aim of present study was to investigate the role of the X-ray repair cross-complementing protein1 (XRCC1) and Tumor protein p53 (Tp53) polymorphisms in Uterine Leiomyoma (UL) susceptibility in southeastern Iran. This case control study was performed on 139 women with UL and 149 age, BMI and ethnicity matched healthy women. All women were genotyped for the XRCC1 Arg399Gln, XRCC1 Arg194Trp and Tp53 Arg72Pro polymorphisms. The frequency of Tp53 72 Pro/Pro genotype was significantly higher in UL women compared to controls. The risk of UL was 1.5 fold higher in women with the Pro/Pro genotype (OR, 1.5 [95% CI, 1.1 to 2.1], p = 0.012). Moreover, the frequency of the Pro allele was significantly higher in the UL women. Although the frequency of XRCC1 Arg399Gln genotypes did not significantly differ between UL and control groups before adjusting for age, there was an association between the XRCC1 Arg/Gln genotype and UL after adjusting for age (OR, 1.8 [95% CI, 1.1 to 3]). No association was observed between the XRCC1 Arg194Trp polymorphism and UL. The Pro/Pro genotype of Tp53 Arg72Pro polymorphism was associated with UL susceptibility. In addition, the XRCC1 Arg/Gln genotype was associated with increased risk of UL after adjusting for age.

Potential Therapeutic Targets in Uterine Sarcomas

Uterine sarcomas are rare tumors accounting for 3,4% of all uterine cancers. Even after radical hysterectomy, most patients relapse or present with distant metastases. The very limited clinical benefit of adjuvant cytotoxic treatments is reflected by high mortality rates, emphasizing the need for new treatment strategies. This review summarizes rising potential targets in four distinct subtypes of uterine sarcomas: leiomyosarcoma, low-grade and high-grade endometrial stromal sarcoma, and undifferentiated uterine sarcoma. Based on clinical reports, promising approaches for uterine leiomyosarcoma patients include inhibition of VEGF and mTOR signaling, preferably in combination with other targeted or cytotoxic compounds. Currently, the only targeted therapy approved in leiomyosarcoma patients is pazopanib, a multitargeted inhibitor blocking VEGFR, PDGFR, FGFR, and c-KIT. Additionally, preclinical evidence suggests effect of the inhibition of histone deacetylases, tyrosine kinase receptors, and the mitotic checkpoint protein aurora kinase A. In low-grade endometrial stromal sarcomas, antihormonal therapies including aromatase inhibitors and progestins have proven activity. Other potential targets are PDGFR, VEGFR, and histone deacetylases. In high-grade ESS that carry the YWHAE/FAM22A/B fusion gene, the generated 14-3-3 oncoprotein is a putative target, next to c-KIT and the Wnt pathway. The observation of heterogeneity within uterine sarcoma subtypes warrants a personalized treatment approach.

Uterine smooth muscle tumor analysis by comparative genomic hybridization: a useful diagnostic tool in challenging lesions

The diagnosis and management of uterine smooth muscle tumors with uncertain malignant potential (STUMP) is often challenging, and genomic data on these lesions as well as on uterine smooth muscle lesions are limited. We tested the hypothesis that genomic profile determination by array-CGH could split STUMP into a benign group with scarce chromosomal alterations akin to leiomyoma and a malignant group with high chromosomal instability akin to leiomyosarcoma. Array-CGH genomic profile analysis was conducted for a series of 29 cases of uterine STUMP. A group of ten uterine leiomyomas and ten uterine leiomyosarcomas served as controls. The mean age was 50 years (range, 24-85) and the follow-up ranged from 12 to 156 months (average 70 months). Since STUMP is a heterogenous group of tumors with genomic profiles that can harbor few to many chromosomal alterations, we compared genomic indices in leiomyomas and leiomyosarcomas and set a genomic index=10 threshold. Tumors with a genomic index <10 were classified as nonrecurring STUMPs and those with a genomic index >10 represented STUMPs with recurrences and unfavorable outcomes. Hence, the genomic index threshold splits the STUMP category into two groups of tumors with different outcomes: a group comparable to leiomyomas and another similar to leiomyosarcomas, but more indolent. In our STUMP series, genomic analysis by array-CGH is an innovative diagnostic tool for problematic smooth muscle uterine lesions, complementary to the morphological evaluation approach. We provide an improved classification method for distinguishing truly malignant tumors from benign lesions within the category of STUMP, especially those with equivocal morphological features.

Molecular analyses of 6 different types of uterine smooth muscle tumors: Emphasis in atypical leiomyoma

BACKGROUND

Uterine smooth muscle tumors (USMTs) constitute a group of histologic, genetic, and clinical heterogeneous tumors that include at least 6 major histologically defined tumor types: leiomyoma (ULM), mitotically active leiomyoma (MALM), cellular leiomyoma (CLM), atypical leiomyoma (ALM), uncertain malignant potential (STUMP), and leiomyosarcoma (LMS). Apart from ULM and LMS, the nature of these variants is not well defined.

METHODS

A total of 167 cases of different USMT variants were collected, reviewed, and diagnostically confirmed based on the World Health Organization and Stanford schemes. These included 38 cases of LMS, 18 cases of STUMP, 42 cases of ALM, 22 cases of CLM, 7 cases of MALM, and 40 cases of ULM. Molecular analysis included selected microRNAs (miRNAs), oncogenes, and tumor suppressors that are highly relevant to USMT.

RESULTS

Overall, 49% (17/35) of LMS cases and 7% (1/14) of STUMP cases died due to their USMT, but no deaths were attributed to ALM. miRNA profiling revealed that ALM and LMS shared similar miRNA signatures. P53 mutations and PTEN deletions were significantly higher in LMS, ALM, and STUMP compared with other USMT variants (P < .01). In contrast, MED12 mutations were extremely common in ULM and MALM (> 74%) but were significantly less common (< 15%) in CLM, ALM, STUMP, and LMS (P < .01).

CONCLUSION

Six types of USMT have different gene mutation fingerprints. ALM shares many molecular alterations with LMS. Our findings suggest that ALM may be a precursor lesion of LMS or have similar genetic changes during its early stage.

Chromosome imbalances and alterations in the p53 gene in uterine myomas from the same family members: familial leiomyomatosis in Turkey

Uterine leiomyomas (UL) are extremely common neoplasms in women of reproductive age, and are associated with a variety of characteristic choromosomal aberrations (CAs). The p53 gene has been reported to play a crucial role in suppressing the growth of a variety of cancer cells. Therefore, the present study investigated the effects of CAs and the p53 gene on ULs. We performed cytogenetic analysis by G-banding in 10 cases undergoing myomectomy or hysterectomy. Fluorescence in situ hybridization (FISH) with a p53 gene probe was also used on interphase nuclei to screen for deletions. In patients, CAs were found in 23.4% of 500 cells analysed, significantly more frequent than in the control group (p<0.001). In the patients, 76% of the abnormalities were structural aberrations (deletions, translocations and breaks), and only 24% were numerical. Deletions were the most common structural aberration observed in CAs. Among these CAs, specific changes in five loci 1q11, 1q42, 2p23, 5q31 and Xp22 have been found in our patients and these changes were not reported previously in UL. The chromosome breaks were more frequent in cases, from high to low, 1, 2, 6, 9, 3, 5, 10 and 12. Chromosome 22, X, 3, 17 and 18 aneuploidy was observed to be the most frequent among all numerical aberrations. We observed a low frequency of p53 losses (2-11%) in our cases. The increased incidence of autosomal deletions, translocations, chromatid breaks and aneuploidy, could contribute to the progression of the disease along with other chromosomal alterations.

Immunohistochemical detection of promyelocytic leukemia zinc finger and histone 1.5 in uterine leiomyosarcoma and leiomyoma

OBJECTIVES

The accurate distinction of leiomyoma from leiomyosarcoma is essential for patient management. However, the distinction can be difficult to make, particularly in tissue biopsy samples. Immunohistochemistry has been established as a useful technique to aid in the diagnosis of malignancies. The advantages of immunohistochemical studies are their ease of use and interpretation. This study is the first to evaluate the utility of the promyelocytic leukemia zinc finger (PLZF) protein and the histone 1.5 (H1.5) protein as potential diagnostic immunohistochemical markers for distinguishing leiomyosarcoma from leiomyoma.

METHODS

Tissue samples from 21 leiomyosarcomas and 26 leiomyomas were studied. The student t-test and the Fisher exact test were used to calculate the differences in staining between the 2 groups.

RESULTS

Statistically significant differences were found in the staining indices of anti-PLZF and anti-H1.5 when comparing benign and malignant tumors (P < .0001 and P < .0001, respectively). The mean H1.5 staining score in leiomyosarcomas was 158.3, compared to 28.3 in leiomyomas. The mean PLZF score in leiomyosarcomas was 1.5 in contrast to 71.5 in leiomyomas. For H1.5 at a score ≥60, the sensitivity and specificity were 90.5% and 84.6%, respectively. For PLZF, a score ≤15 had a test sensitivity and specificity of 100% and 80.8%, respectively. This suggests that staining for H1.5 or PLZF can serve as a good screening test. Additionally, combining the 2 immunostains results in a sensitivity and specificity of 90.5% and 97.5%, respectively, in differentiating between leiomyoma and leiomyosarcoma.

CONCLUSIONS

We describe immunostaining for PLZF and H1.5 in benign and malignant uterine smooth muscle tumors. Statistically significant differences in staining patterns were found, suggesting utility in distinguishing leiomyosarcomas from leiomyomas.

[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.

A "twist box" code of p53 inactivation: twist box: p53 interaction promotes p53 degradation

Twist proteins have been shown to contribute to cancer development and progression by impinging on different regulatory pathways, but their mechanism of action is poorly defined. By investigating the role of Twist in sarcomas, we found that Twist1 acts as a mechanism alternative to TP53 mutation and MDM2 overexpression to inactivate p53 in mesenchymal tumors. We provide evidence that Twist1 binds p53 C terminus through the Twist box. This interaction hinders key posttranslational modifications of p53 and facilitates its MDM2-mediated degradation. Our study suggests the existence of a Twist box code of p53 inactivation and provides the proof of principle that targeting the Twist box:p53 interaction might offer additional avenues for cancer treatment.

Oncofetal protein IMP3: a useful diagnostic biomarker for leiomyosarcoma

An accurate diagnosis between leiomyoma and leiomyosarcoma is essential for patient management. IMP3 is a member of the insulin-like growth factor (IGF-II) mRNA binding protein (IMP) family that consist of IMP1, IMP2, and IMP3. IMP3 is an oncofetal protein associated with aggressive and advanced tumors and is specifically expressed in malignant tumors but not found in benign tissues. The aim of this study was to determine the expression and diagnostic value of IMP3 in leiomyoma and leiomyosarcoma. A total of 216 cases (resection, n = 183; biopsy, n = 33) consisting of 82 leiomyosarcomas (uterine, n = 15; soft tissue, n = 67), 62 leiomyomas (uterine, n = 50; soft tissue, n = 12), and 72 uterine-variant leiomyomas (atypical, n = 19 [14%]; cellular, n = 21 [16%]; mitotically active, n = 12 [9%]; myxoid, n = 11 [8%]; vascular, n = 3 [2%]; epithelioid, n = 1 [1%]; benign metastasizing, n = 1 [1%]; and smooth muscle tumors of uncertain malignant potential, n = 4) were examined by immunohistochemistry for IMP3 expression. IMP3 showed strong cytoplasmic staining in 43 (52%) of 82 leiomyosarcomas, regardless of histologic grades. There was no difference in IMP3 expression between uterine and soft tissue leiomyosarcomas. In contrast to malignant tumors, IMP3 expression was not found in any of the typical leiomyomas (0/62 cases). All uterine-variant leiomyomas were negative, except for 3 cases (atypical variant, n = 2; cellular variant, n = 1) for IMP3 staining. In summary, we are the first to describe IMP3 expression in smooth muscle tumors. Our findings indicate that the expression of IMP3 in both uterine and soft tissue leiomyosarcomas can be used as a positive biomarker to increase the level of confidence in establishing a definitive diagnosis of a malignant smooth muscle tumor.

Lipoleiomyosarcoma of the larynx

BACKGROUND

Lipoleiomyosarcoma is a rare tumor consisting of well-differentiated liposarcoma and leiomyosarcoma. The ear-nose-throat location of lipoleiomyosarcoma has not been previously described.

METHODS AND RESULTS

A 37-year-old man with a dysphagia had a dyspnea after an endoscopy. A large tumor was exteriorized from the man's mouth. The lesion was pedicled to the epiglottis. A histologic examination determined that the tumor was a lipoleiomyosarcoma. MDM2 and CDK4 gene amplification were positive. Due to the risk of recurrence, a second intervention was performed to complete the excision.

CONCLUSION

These tumors develop in cavities slowly and gradually. The treatment of this lesion is surgical with a sufficient resection margin.

Targeting the p53 Pathway in Ewing Sarcoma

The p53 tumour suppressor plays a pivotal role in the prevention of oncogenic transformation. Cancers frequently evade the potent antitumour surveillance mechanisms of p53 through mutation of the TP53 gene, with approximately 50% of all human malignancies expressing dysfunctional, mutated p53 proteins. Interestingly, genetic lesions in the TP53 gene are only observed in 10% of Ewing Sarcomas, with the majority of these sarcomas expressing a functional wild-type p53. In addition, the p53 downstream signaling pathways and DNA-damage cell cycle checkpoints remain functionally intact in these sarcomas. This paper summarizes recent insights into the functional capabilities and regulation of p53 in Ewing Sarcoma, with a particular focus on the cross-talk between p53 and the EWS-FLI1 gene rearrangement frequently associated with this disease. The development of several activators of p53 is discussed, with recent evidence demonstrating the potential of small molecule p53 activators as a promising systemic therapeutic approach for the treatment of Ewing Sarcomas with wild-type p53.

Uterine smooth muscle tumors of uncertain malignant potential (STUMP): a clinicopathologic analysis of 16 cases

BACKGROUND

The current World Health Organization classification indicates that a uterine smooth muscle tumor that cannot be histologically diagnosed as unequivocally benign or malignant should be termed "smooth muscle tumor of uncertain malignant potential" (STUMP). STUMPs represent a heterogeneous group of rare tumors that have been the subject of only a few published studies, some of which lack detailed clinicopathologic details and/or follow-up data. More recently, it has been suggested that immunohistochemical staining may be helpful in the diagnosis of STUMPs.

DESIGN

The clinicopathologic features of 16 cases of STUMP that exhibited usual smooth muscle differentiation, diagnosed between 1992 and 2006 from 11 hospitals, were studied and classified into 4 subgroups using terminology and criteria described by Stanford investigators. Immunohistochemical stains for p16, p53, MIB1 (ki-67), and estrogen and progesterone receptors were performed. The results were compared with those in the literature.

RESULTS

The tumors were classified as follows: 6 as "atypical leiomyoma with limited experience", 7 as "smooth muscle tumor of low malignant potential", 2 as "atypical leiomyoma, low risk of recurrence," and 1 as "mitotically active leiomyoma, limited experience." Follow-up was 21 to 192 months (mean, 80.8 and median, 51.5). Only 2 tumors recurred, at 15 and 51 months, respectively; both were atypical leiomyoma with limited experience (multifocal moderate-to-severe atypia, no tumor cell necrosis, and mitotic counts of 4 and 5 mitotic figures /10 high-power fields, respectively). Both tumors had areas that were indistinguishable from benign leiomyoma and both had diffuse immunoreactivity for p16 and p53. Six other tumors that had focal staining for these markers all had a benign outcome. Both patients with recurrence were alive at last follow-up (at 40 and 74 mo). All the other patients were alive and disease-free.

CONCLUSIONS

This and other studies suggest that uterine tumors classified as STUMPs using criteria proposed by Stanford investigators are usually clinically benign but should be considered tumors of low malignant potential because they can occasionally recur, in some cases, years after hysterectomy. After a mean follow-up of 80.8 months, only 2 of 16 tumors in this study recurred. Both of the latter tumors fulfilled the criteria for atypical leiomyoma with limited experience. Notably, the 2 recurrent tumors were the only ones that were strongly immunoreactive for p16 and p53, supporting earlier observations that these markers may be helpful in the prediction of the behavior of STUMPs. Patients diagnosed with STUMPs should receive long-term surveillance.

A panel of antibodies to determine site of origin and malignancy in smooth muscle tumors

Leiomyosarcomas are malignant smooth muscle tumors that occur most commonly in the gynecologic tract and soft tissue. There are different diagnostic criteria of malignancy for smooth muscle tumors arising at gynecologic and soft tissue sites and they may be managed differently but determining the primary site of a smooth muscle tumor can be difficult in some cases. In addition, the distinction between malignant and benign gynecologic tract smooth muscle tumors on morphologic grounds can be challenging. Using a series of tissue microarrays that contain 245 cases of leiomyosarcomas (102 gynecologic) with survival data, and 49 cases of uterine leiomyoma, we examined the ability of selected immune-markers (estrogen receptor (ER) and WT1) to distinguish between leiomyosarcomas of gynecologic and nongynecologic origin. In addition, we examined whether immunostains for p16, p53 and Ki-67 could distinguish between malignant and benign gynecologic smooth muscle tumors. ER nuclear positivity was observed in 3 and 50% of the nongynecologic and gynecologic leiomyosarcomas, respectively (P<0.001). Nuclear WT1 positivity was seen in 0 and 8% of the nongynecologic and gynecologic leiomyosarcomas, respectively (P<0.001). 87% of primary gynecologic leiomyosarcomas and 2% of uterine leiomyomas showed diffuse (>or=50% of cells) p16 staining (P<0.001). 23% of gynecologic leiomyosarcomas showed p53 immunopositivity (>or=50% of cells) whereas none of the leiomyomas were positive for p53 (P<0.001). 65% of the gynecologic leiomyosarcomas and 0% of the leiomyomas exhibited >10% Ki-67 proliferation index (P<0.001). Diffuse p16 and p53 immunopositivity and high Ki-67 proliferation index, singly or in combination, yielded an overall sensitivity of 92% and specificity of 98% for distinguishing between gynecologic leiomyosarcomas and leiomyomas and can be used as indicators of malignancy for gynecologic smooth muscle tumors. Although ER positivity can be used to support the gynecologic origin of a leiomyosarcomas, nuclear WT1 immunostaining is of little use.

Lipoleiomyosarcoma of the rectosigmoid colon: a unique site for a rare variant of liposarcoma

OBJECTIVES

Soft tissue tumors with dual adipocytic and smooth muscle differentiation are generally rare with most being benign. Sarcomas with dual fatty and smooth muscle differentiation are even rarer. The purpose of this paper is to discuss a rare presentation of a lipoleiomyosarcoma and review, the method of pathologic diagnosis and the literature.

METHODS

Detailed clinical and histopathologic review of a clinical case and review of the literature using PUBMED for publications on lipoleiomyosarcoma.

RESULTS

Based on the literature, lipoleiomyosarcomas favor body cavities and visceral sites although an occurrence in the intestine has been reported. Pathologic diagnosis requires immunohistochemical staining with MDM2 and CDK4.

CONCLUSIONS

This is the first reported case of an intestinal lipoleiomyosarcoma. Its diagnosis requires immunohistochemistry and awareness of its possible existence.

The Use of p16 in enhancing the histologic classification of uterine smooth muscle tumors

BACKGROUND

Uterine smooth muscle tumors can usually be divided histologically into leiomyoma (L) and leiomyosarcoma (LMS). Occasionally, the histologic features are indeterminate and classified as smooth muscle tumor of uncertain malignant potential (STUMP). Recent gene expression studies have found p16 overexpressed in LMS when compared with normal myometrium. This study evaluated the protein expression of p16 by immunohistochemistry in LMS, L, and normal myometrium. Additionally, 8 tumors originally classified as STUMP were evaluated for p16 expression and correlated to their clinical outcome.

METHODS

A tissue microarray was constructed and composed of 15 LMS, 8 STUMPs, 22 L, and 10 samples of normal myometrium. p16 expression was correlated with clinical outcome and histologic features.

RESULTS

Twelve of the 15 LMS strongly and diffusely expressed p16, 3 of the L had focal p16 staining, and none of the normal myometria were p16 positive. Three of the tumors originally classified as STUMP developed metastatic disease and 2 of these tumors had strong, diffuse p16 positivity. Histologically, these 2 cases were characterized by coagulative tumor cell necrosis and only mild cytologic atypia.

CONCLUSIONS

p16 is preferentially expressed in LMS with only rare L showing positivity. Histologically, tumors with coagulative tumor cell necrosis alone were clinically LMS. In those cases in which the type of necrosis is uncertain (coagulative tumor cell vs. hyalinized), the addition of p16 may aid in discerning a subset of STUMP that should be classified as LMS.

Prognostic significance of p53 gene mutations and protein overexpression in localized gastrointestinal stromal tumours

AIMS

Mutation of c-kit is a relatively early event in the tumorigenesis of gastrointestinal stromal tumours (GISTs). The aim was to determine the prognostic significance of p53 alterations as an additional genetic change in GISTs.

METHODS AND RESULTS

We reviewed 125 patients with localized GISTs subjected to complete resection between 1990 and 2002. Mutational analyses of c-kit exons 9, 11, 13 and 17, p53 exons 4-8 and immunohistochemistry for p53 protein were conducted using paraffin-embedded tissues. Alterations of p53 were observed in 50 patients (40.0%). Based on the National Institutes of Health's risk category, p53 alterations were noted more frequently in the higher risk categories (P = 0.041). With a median follow-up of 56.5 months (range: 2.3-126.8), 5-year relapse-free survival (RFS) rates were 61.7% without p53 alterations, compared with only 40.2% with p53 alterations (P = 0.009). Multivariate analysis indicated that p53 alterations comprised an independent, poor prognostic factor for RFS, in addition to c-kit mutations, large size, a high mitotic count and non-gastric primary sites.

CONCLUSIONS

Alterations in p53 were more commonly observed in localized GISTs at higher risk of relapse. This suggests that they are significant as an independent, poor prognostic factor.

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.

The MDM2 promoter polymorphism SNP309T-->G and the risk of uterine leiomyosarcoma, colorectal cancer, and squamous cell carcinoma of the head and neck

BACKGROUND

MDM2 acts as a principal regulator of the tumour suppressor p53 by targeting its destruction through the ubiquitin pathway. A polymorphism in the MDM2 promoter (SNP309) was recently identified. SNP309 was shown to result, via Sp1, in higher levels of MDM2 RNA and protein, and subsequent attenuation of the p53 pathway. Furthermore, SNP309 was proposed to be associated with accelerated soft tissue sarcoma formation in both hereditary (Li-Fraumeni) and sporadic cases in humans.

METHODS

We evaluated the possible contribution of SNP309 to three tumour types known to be linked with the MDM2/p53 pathway, using genomic sequencing or restriction fragment length polymorphism as screening methods. Three separate Finnish tumour materials (population based sets of 68 patients with early onset uterine leiomyosarcomas and 1042 patients with colorectal cancer, and a series of 162 patients with squamous cell carcinoma of the head and neck) and a set of 185 healthy Finnish controls were analysed for SNP309.

RESULTS

Frequencies of SNP309 were similar in all four cohorts. In the colorectal cancer series, SNP309 was somewhat more frequent in women and in patients with microsatellite stable tumours. Female SNP309 carriers were diagnosed with colorectal cancer approximately 2.7 years earlier than those carrying the wild type gene. However, no statistically significant association of SNP309 with patients' age at disease onset or to any other clinicopathological parameter was found in these three tumour materials.

CONCLUSION

SNP309 had no significant contribution to tumour formation in our materials. Possible associations of SNP309 with microsatellite stable colorectal cancer and with earlier disease onset in female carriers need to be examined in subsequent studies.

p53, epidermal growth factor, and platelet-derived growth factor in uterine leiomyosarcoma and leiomyomas

Uterine leiomyosarcoma (ULMS) is an aggressive gynecological disease. Although ULMS are often found in association with benign leiomyoma (LMA), little is known regarding the relationship between these benign and malignant smooth muscle neoplasms. The objective of this study was to evaluate the expression of epidermal growth factor (EGFR), platelet-derived growth factor (PDGFR), and p53 in ULMS specimens, their prognostic relevance, and the expression of these molecular markers when compared to benign LMA specimens. Between 1991 and 2001, 25 patients were identified with high-grade primary ULMS and for whom tissue was available. Tissue microarray was created with three representative cores from each of the ULMS cases as well as from 19 patients with benign uterine leiomyomata. Immunohistochemical (IHC) staining was performed for EGFR, PDGFR, and p53. Negative and positive IHC staining was scored for each marker. Outcome analysis was performed only for ULMS. Survival was determined from the time of initial diagnosis to last follow-up. Twelve (48%) ULMS expressed p53 compared to none of the LMA (P < 0.001), and 15 (60%) ULMS cases showed PDGFR expression compared to 32% of LMA samples (P= 0.08). EGFR expression did not differ between ULMS and LMA groups. ULMS patients with p53 expression had a poorer survival compared to ULMS patients with negative expression (P= 0.07). ULMS tumor stage had the strongest association with overall survival (P= 0.05). Our study supports previous investigations indicating that p53 expression may serve as a prognostic marker for ULMS patients. The difference in PDGFR expression between ULMS and LMA demonstrated a trend toward significance. EGFR was not commonly expressed in ULMS. These uniquely expressed markers may assist in stratifying patients by survival and identify novel therapeutic markers. Clearly, further investigation is needed.

7q deletion mapping and expression profiling in uterine fibroids

Uterine fibroids are some of the most common tumours of females, but relatively little is known about their molecular basis. Several studies have suggested that deletions on chromosome 7q could have a role in fibroid formation. We analysed 165 sporadic uterine fibroids to define a small 3.2 megabase (Mb) commonly deleted region on 7q22.3-q31.1, flanked by clones AC005070 and AC007567. We also used oligonucleotide microarrays to compare the expression profiles of 10 samples of normal myometrium and 15 fibroids, nine of which displayed 7q-deletions. Activating transcription factor 3, patched homolog (Drosophila), homeo box A5, death-associated protein kinase 1, and retinoic acid receptor responder 3 were downregulated, and excision repair crosscomplementing 3, transcription factor AP-2 gamma and protein kinase C beta 1 were upregulated in fibroids. New pathways were discovered related to fibroid formation. The presence or absence of 7q-deletions did not dramatically affect the global expression pattern of the tumours; changes, however, were observed in genes related to vesicular transport and nucleic acid binding.

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.

Tumor necrosis factor-alpha-308 promoter and p53 codon 72 gene polymorphisms in women with leiomyomas

OBJECTIVE

Tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, plays an important role in the process of autoimmune diseases. p53 is related to the regulation of cell growth and prevention of carcinogenesis. We propose to investigate whether gene polymorphisms for TNF-alpha-308 promoter and p53 could be used as markers of susceptibility in leiomyomas.

DESIGN

Prospective basic study.

SETTING

Departments of gynecology and genetics in a medical center.

PATIENT(S)

Group 1: leiomyoma (n = 159); group 2: non-leiomyoma (n = 131).

INTERVENTION(S)

Genomic DNA was obtained from peripheral leukocyte. The TNF-alpha and p53 gene polymorphisms were amplified by polymerase chain reaction (PCR), enzyme restriction, and electrophoresis.

MAIN OUTCOME MEASURE(S)

Two gene polymorphisms were identified: [1] the A (cuttable)/G (uncuttable) polymorphisms of the TNF-alpha gene on chromosome 6p21.3; [2] A (cuttable)/P (uncuttable) polymorphisms of the p53 gene on chromosome 17p. Genotype and allelic frequencies in both groups were compared.

RESULT(S)

Genotype distribution and allele frequency of TNF-alpha gene polymorphism in both groups were significantly different. Proportions of A homozygote/heterozygote/G homozygote for TNF-alpha in both groups were: (group 1) 61%/34.6%/4.4% and (group 2) 81.7%/14.5%/3.8%. Proportions of allele A/G for TNF-alpha in both groups were: (group 1) 78.3%/21.7% and (group 2) 88.9%/11.1%. Distributions of p53 polymorphisms in both groups were not different. The proportions of A homozygotes/heterozygotes/P homozygotes for p53 were (group 1) 32.7%/42.1%/25.2% and (group 2) 28.2%/48.9%/22.9%.

CONCLUSION(S)

G homozygote and G allele for TNF-alpha promoter are related to a higher risk of leiomyomas. The p53 codon 72 gene polymorphism is not associated with the susceptibility of leiomyomas.

Biallelic inactivation of fumarate hydratase (FH) occurs in nonsyndromic uterine leiomyomas but is rare in other tumors

Germline mutations in the fumarate hydratase (FH) gene at 1q43 predispose to dominantly inherited cutaneous and uterine leiomyomas, uterine leiomyosarcoma, and papillary renal cell cancer (HLRCC syndrome). To evaluate the role of FH inactivation in sporadic tumorigenesis, we analyzed a series of 299 malignant tumors representing 10 different malignant tumor types for FH mutations. Additionally, 153 uterine leiomyomas from 46 unselected individuals were subjected to and informative in loss of heterozygosity analysis at the FH locus, and the five (3.3%) tumors displaying loss of heterozygosity were subjected to FH mutation analysis. Although mutation search in the 299 malignant tumors was negative, somatic FH mutations were found in two nonsyndromic leiomyomas; a splice site change IVS4 + 3A>G, leading to deletion of exon four, and a missense mutation Ala196Thr. The occurrence of somatic mutations strongly suggests that FH is a true target of the 1q43 deletions. Although uterine leiomyomas are the most common tumors of women, specific inactivating somatic mutations contributing to the formation of nonsyndromic leiomyomas have not been reported previously. Taking into account the apparent risk of uterine leiomyosarcoma associated with FH germline mutations, the finding raises the possibility that also some nonsyndromic leiomyomas may have a genetic profile that is more prone to malignant degeneration. Our data also indicate that somatic FH mutations appear to be limited to tumor types observed in hereditary leiomyomatosis and renal cell cancer.

Mutation analysis of CDP, TP53, and KRAS in uterine leiomyomas

Leiomyomas are the most common gynecologic tumors in women, but very little is known about their molecular pathology. We used single-stranded conformational polymorphism/heteroduplex analysis to analyze 42 unselected uterine leiomyomas for somatic mutations in all coding exons of the gene encoding CCAAT displacement protein (CDP), as well as exons 5-8 of TP53 and codons 1-36 and 38-80 of KRAS. No somatic mutations were identified in either TP53 or KRAS, indicating that disregulation of these genes is not required for leiomyomas development. Aberrant band shifts were identified in CDP, but these were all germline nonpathogenic variants that have been reported previously. There is good functional and genetic evidence indicating that CDP is a leiomyoma suppressor, but our data suggested that somatic mutations in this gene were rare in unselected uterine leiomyomas. It is possible that CDP belongs to a class of tumor suppressor in which loss of only one copy of the gene, either by genetic or epigenetic mechanisms, is sufficient to allow tumor growth.

Increased expression of cyclin G1 in leiomyoma compared with normal myometrium

OBJECTIVE

The purpose of this study was to detect the expression of cyclin G1 in leiomyoma and to investigate the alteration of its expression compared with normal myometrial tissue that was obtained from the same patient.

STUDY DESIGN

With the use of Northern blot analysis, Western blot analysis, and immunohistochemistry, we analyzed the expression of cyclin G1 in 24 patients who underwent hysterectomies.

RESULTS

We found that messenger RNA levels of cyclin G1 were elevated in human leiomyomas compared with their adjacent normal myometrial tissues. Consistent with elevated messenger RNA levels, high levels of cyclin G1 protein expression were detected by immunoblot analysis in all leiomyoma samples. Immunohistochemistry revealed that cyclin G1 is located mainly in the nucleus in both normal myometrium and leiomyoma. However, higher levels of cyclin G1 were apparent in tumor regions compared with adjacent normal myometrial regions. In addition, we found the expression levels of other cyclins (A and E) and CDK2 were elevated in leiomyomas compared with normal myometrium. Because cyclin G1 is a transcriptional target of the p53 tumor suppressor, we examined the p53 status of all eight leiomyoma samples and found no p53 mutations.

CONCLUSION

These results suggest that cyclin G1 is frequently overexpressed in uterine leiomyoma in a p53-independent manner and that this abnormality could be attributed to the severe proliferation of human uterine leiomyomas.

Oral leiomyosarcoma: review of the literature and report of two cases with assessment of the prognostic and diagnostic significance of immunohistochemical and molecular markers

Leiomyosarcoma of the oral cavity is a very rare tumor that is associated with aggressive clinical behavior and low survival. In this paper, we report two new cases of leiomyosarcoma affecting the mandibular gingiva and mandible of a 35-year-old male and the mandible of a 51-year-old female. Given the difficulty in the histopathologic discrimination between benign and malignant smooth muscle tumors and the absence of reliable histologic parameters for prognostication of leiomyosarcomas, we evaluated the diagnostic and prognostic value of various immunohistochemical and molecular markers. By means of immunohistochemistry and quantitative real-time PCR analysis, we detected protein expression of PCNA, bcl-2, CDK4, p53 and MDM2 in both our cases and MDM2 amplification in our second case. The literature, pertinent to oral leiomyosarcoma and to molecular analysis of smooth muscle tumors, is reviewed.

MIB-1 (Ki-67), p53, estrogen receptor, and progesterone receptor expression in uterine smooth muscle tumors

The diagnosis of benign, uncertain malignant potential, and malignant uterine smooth muscle tumors depends on mitotic counts, nuclear atypia, and other morphologic features. This study was undertaken to evaluate the utility of selected immunohistochemical markers in differentiating these tumors. Fifteen cases of cellular leiomyoma, 7 cases of smooth muscle tumor of uncertain malignant potential (STUMP), and 12 cases of leiomyosarcoma were immunostained for MIB-1 (Ki-67), p53, estrogen receptor and progesterone receptor (PR) using monoclonal antibodies and the avidin-biotin-peroxidase method. The percentage of cells stained was subjectively assessed to the nearest 5%. One percent was used for rare positive cells. MIB-1 expression of > or =15% was seen in 11 and expression of p53 in > or =15% cells was present in 5 of 12 leiomyosarcomas. MIB-1 and/or p53 expression of >15% was seen in all 12 leiomyosarcomas but in none of the 7 STUMP or 15 cellular leiomyomas. PR was absent in 10 of 12 leiomyosarcomas but present in 7 of 7 STUMP and 14 of 15 cellular leiomyomas. MIB-1 of 5% to 10% was seen in 6 of 7 STUMP but in only 1 of 15 cellular leiomyomas. MIB-1, p53, and PR are useful in differentiating leiomyosarcoma from STUMP and cellular leiomyoma. MIB-1 is useful in distinguishing STUMP from cellular leiomyomas.

In situ detection of unexpected patterns of mutant p53 gene expression in non-small cell lung cancers

Many solid tumors, including non-small cell lung cancers (NSCLCs), are characterized by heterogenous expression of p53 protein in the neoplastic cells. To analyse the molecular implications of this finding, we examined topographic distribution of p53 mutations using in situ polymerase chain reaction (PCR) in primary NSCLCs, showing distinct patterns of variable p53 overexpression by immunohistochemistry. Unique sets of primers for each mutation were designed, and optimal PCR conditions were determined by standard PCR using DNA from cloned mutants or cell lines established from these tumors. All tumor cell nuclei, regardless of the status of p53 overexpression, demonstrated homogeneous distribution of mutant p53 with specific primers, indicating that only subgroups of the mutated cells overexpressed p53 protein. In situ reverse transcription (RT)-PCR was applied to detect mutant mRNA in the individual tumor cells using specific primers. We found that in each case the distribution of mutant p53 mRNA coincided with that of immunohistochemical overexpression of p53 protein. Our results suggest that the regulation of mutant p53 expression, but not the genotype, is heterogeneous in the neoplastic cells. The topographic genomapping of p53 in NSCLC using in situ PCR provides a novel approach to view molecular mechanisms of lung carcinogenesis.

Characterization of chromosome aberrations associated with soft-tissue leiomyosarcomas by twenty-four-color karyotyping and comparative genomic hybridization analysis

Data on the chromosome aberrations associated with leiomyosarcomas of soft tissues are limited, complex, and incomplete. The aim of this study was to characterize genetic aberrations associated with this tumor group, to identify consistent regions of involvement and to determine correlations with clinical outcome. Chromosomes were prepared from 10 primary soft-tissue leiomyosarcoma samples, and preparations from four of them, plus the cell line SK-LMS-1, were suitable for analysis using 24-color karyotyping by multifluor fluorescence in situ hybridization. This method allowed rearranged chromosomes to be characterized, which would not have been possible by banding analysis alone. The remaining six chromosome preparations were analyzed using standard Giemsa banding. The chromosome imbalances associated with all the samples were determined by comparative genomic hybridization analysis. Taken together, the results show both intra- and intertumor heterogeneity and considerable complexity. Although no highly consistent rearrangements were found, some regions of the genome frequently were involved, including 1q21, 5p14-pter, and 20q13, which likely harbor genes that play a role in the pathogenesis of soft-tissue leiomyosarcomas. There were no obvious correlations between the chromosomal changes identified and available clinical details.