Mast cells in smooth muscle tumors of the uterus

Therapeutic Effects of Long-Term Administration of Tranilast in an Animal Model for the Treatment of Fibroids

Tranilast (N-3, 4-dimethoxycinnamoyl anthranilic acid) is an orally administered drug with antiallergic properties and approved in Japan and the Republic of Korea for the treatment of asthma and hypertrophic scars. Previous in vitro studies indicated that tranilast reduced fibroid growth through its inhibitory effects on cell proliferation and induction of apoptosis. The objective of this study was to determine the efficacy of tranilast for treatment of human-derived fibroids in a mouse model. SCID mice (ovariectomized, supplemented with estrogen and progesterone) were implanted with fibroid explants and treated for two months with tranilast (50 m/kg/daily) or the vehicle. After sacrifice, xenografts were excised and analyzed. Tranilast was well tolerated without adverse side effects. There was a 37% reduction in tumor weight along with a significant decrease in staining for Ki67, CCND1, and E2F1; a significant increase in nuclear staining for cleaved caspase 3; and reduced staining for TGF-β3 and Masson's trichrome in the tranilast treated mice. There was a significant inhibition of mRNA and protein expression of fibronectin, COL3A1, CCND1, E2F1, and TGF-β3 in the xenografts from the tranilast-treated mice. These promising therapeutic effects of tranilast warrant additional animal studies and human clinical trials to evaluate its efficacy for treatment of fibroids.

Tranilast induces MiR-200c expression through blockade of RelA/p65 activity in leiomyoma smooth muscle cells

OBJECTIVE

To determine the mechanism by which tranilast induces miR-200c expression in leiomyoma smooth muscle cells (LSMCs).

DESIGN

Experimental study.

SETTING

Academic research laboratory.

PATIENT(S)

Women undergoing hysterectomy for leiomyoma.

INTERVENTION(S)

Blockade of RelA/p65.

MAIN OUTCOME MEASURE(S)

Effects of tranilast and blockade of RelA/p65 on miR-200c expression.

RESULT(S)

Tranilast, an inflammation inhibitor, dose-dependently induced miR-200c in LSMCs and myometrium smooth muscle cells (MSMCs), with a more profound effect in LSMCs than in MSMCs. The treatment of LSMCs with Bay 117082, an inhibitor of IκB phosphorylation, further enhanced miR-200c induction by tranilast. The knockdown of RelA/p65 by small interfering RNA also induced miR-200c expression in LSMCs. Although tranilast had no effect on total RelA/p65 protein levels in LSMCs, it significantly induced RelA/p65 phosphorylation at S536 while reducing its activity as well as its nuclear translocation. ChIP assay indicated that tranilast reduces the binding ability of RelA/p65 to miR-200c promoter, resulting in miR-200c induction. Tranilast also inhibited interleukin-8 (IL8) expression in LSMCs. The induction of miR-200c by tranilast partially mediates the inhibitory effect of tranilast on the expression of IL8 and cyclin-dependent kinase 2 in LSMCs.

CONCLUSION(S)

Induction of miR-200c by tranilast in LSMCs is mediated through a transcriptional mechanism involving inhibition of the nuclear factor κB signaling pathway. These results highlight the significance of inflammation in the pathogenesis of leiomyoma and the potential utility of antiinflammatory drugs for treatment of leiomyomas.

Pathological evaluation of uterine leiomyomas treated with gonadotropin-releasing hormone agonist (GnRH-a) therapy: role of mast cells and a possible mechanism of GnRH-a resistance in leiomyomas

Gonadotropin-releasing hormone agonist (GnRH-a) therapy is frequently applied to reduce the volume of uterine leiomyomas (UL). In addition, the possible relationship between mast cells (MC) within UL and the development of UL has been suggested, but the role of MC in UL remains to be determined. UL with or without GnRH-a therapy in 121 premenopausal patients were reviewed. The number of MC was evaluated between the two groups, immunohistochemistry was done for insulin-like growth factor-I (IGF-I), and the association between the IGF-I immunoreactivity in UL and the GnRH-a therapy was analyzed. The number of MC significantly increased in UL in GnRH-a therapy, while IGF-I immunoreactivity was significantly reduced in smooth muscle cells of these UL. Furthermore, IGF-I immunoreactivity in MC was inversely correlated with the size reduction rate of UL in GnRH-a therapy. Although GnRH-a therapy is considered to reduce the size of UL transiently, the regression of UL was in part hampered by the increased IGF-I secretion from the increased MC after GnRH-a therapy. Therefore, the more the IGF-I secretion from MC in UL increases, the less effective the GnRH-a therapy is on the size reduction of UL. Thus, the present study may provide an explanation of the possible mechanism of GnRH-a resistance in UL.

Large angioleiomyoma, rich of mast cell and sex hormone receptor expression

BACKGROUND

Angioleiomyoma is a rare benign solitary tumor, arising from the vascular smooth muscle. This tumor usually occurs in the subcutis of extremities, uncommonly in abdomen, often presents as a small (<2 cm) and is treated with excision.

CASE

We report an extremely rare case of unusually large angioleiomyoma, first diagnosed as an ovarian tumor with some malignant possibilities by diagnostic imaging. We resected 1.7 kg of tumor from the extra-peritoneal cavity in the lower abdomen. Histological study revealed that this case's angioleiomyoma had abundant mast cells and sex hormone receptor expression.

CONCLUSION

This angioleiomyoma is not an obvious malignant tumor because of low mitosis, coagulative necrosis and cellular atypia. However, it seems to have low potential malignancy, because it has massive size, marked degeneration and abundant mast cells. There are some possibilities that sex hormones are related with the growth and degeneration of this case's tumor, because those receptors are strongly expressed in the nucleus of tumor cells.

A quantitative and morphometric study of tryptase-positive mast cells in cutaneous leprosy lesions

While mast cells are known to induce differences in the matrix structures, microvascular patterns, and immune responses in a number of diseases, the possible role of mast cells in these same processes over the spectrum of leprosy has not yet been investigated. Thus, ascertaining the possible influence of mast cells in the outcome of the anti-leprosy response to Mycobacterium leprae is of major importance. In this study, 51 cutaneous biopsies of leprosy patients were stained with anti-tryptase antibody in order to quantify mast cells in leprosy lesions and compare the number and size of these cells in all the forms of leprosy. Biopsies were grouped according to an adapted Ridley-Jopling clinical-immunological classification (17 T, 17 B and 17 L). It was found that the L (lepromatous leprosy) group had the lowest dermal mast cell density values among the three groups studied. Furthermore, the average mast cell cross-sectional area was significantly higher in the L in comparison to the B (borderline-borderline) and T (tuberculoid) biopsies, suggesting mast cell functional differences within the groups. The higher mast cell density in the T and B groups was considered indirect evidence of the role of mast cells in the activated immune response to M. leprae infection.

Tryptase- and leptin-positive mast cells correlate with vascular density in uterine leiomyomas

OBJECTIVE

In vitro and in vivo studies have linked mast cell (MC) degranulation and activation with angiogenesis and neovascularization. This assumption is partially supported by the close anatomical association between MC and the vasculature and the recruitment of these cells during tumor growth. The aim of this study was to correlate the extent of angiogenesis with the number of MC expressing tryptase and leptin in human leiomyomas.

STUDY DESIGN

Tissues from human leiomyomas and control specimens were investigated immunohistochemically, using murine monoclonal antibodies against the endothelial cell marker CD31, leptin, and the MC marker tryptase.

RESULTS

Angiogenesis, measured as microvessel counts, was highly correlated with MC tryptase- and leptin-positive cell counts.

CONCLUSION

These data suggest that angiogenesis in leiomyomas is correlated to expression of tryptase in MC granules and provide for the first time evidence of a putative role of leptin, also contained in MC secretory granules, in MC-dependent angiogenesis.

Smooth muscle hamartoma of the hard palate

A small polypoid lesion was removed from the incisive papilla region of a healthy female aged 8 years. It was composed of non-cycling smooth muscle fibres that were immunoreactive for various muscle antigens, surrounded by basement membrane containing collagen IV, arranged as bundles and mixed with CD34(+) interstitial cells, mast cells, dendrocytes and nerves. The lesion could be attributed to dysgenesis affecting media of vessels emerging from the incisive foramen. Intra-oral smooth muscle hamartomas tend to favour regions featuring complex developmental events.

Expression of chemokines CCL5 and CCL11 by smooth muscle tumor cells of the uterus and its possible role in the recruitment of mast cells

OBJECTIVE

Smooth muscle tumors of uterus have been reported to contain considerable number of mast cells, especially cellular leiomyoma. However, to our knowledge the mechanism by which mast cells increased in them is not known. The purpose of this study was to reveal the different mast cell subsets in smooth muscle tumors of uterus and to investigate the mechanism of local increase of mast cells.

METHODS

Tissue sections from 85 uterine smooth muscle tumors were studied using immunohistochemical double labeling techniques, including 40 cases of ordinary leiomyomas, 30 cases of cellular leiomyomas and 15 cases of leiomyosarcomas. The sections were double immunostained for mast cell tryptase and chymase, mast cell tryptase and ki-67, mast cell tryptase and chemokines (i.e., CCL2, CCL5, CCL11, TGFbeta), as well as tryptase and CCR3.

RESULTS

MC(TC)-type of mast cells was the predominant type in ordinary leiomyoma and cellular leiomyoma, whereas MC(T)-type was seldom found in them. There was no MC(C) in smooth muscle tumors. The total intratumoral number of mast cells in cellular leiomyoma group was significantly higher than that in both leiomyosarcoma and ordinary leiomyoma (P<0.01). Mast cells proliferation was rarely detected in smooth muscle tumors, as revealed by constant negative labeling of the proliferation marker Ki-67 in mast cells. Almost all mast cells (tryptase positive) in smooth muscle tumors were also CCL2, CCL5, CCL11 and TGFbeta positive. Expressions of CCL5 and CCL11 in tumor cells in cellular leiomyoma were all significantly higher than that in both ordinary leiomyoma and leiomyosarcoma (P<0.01). While the expression of TGFbeta in tumor cells in cellular leiomyoma was not significantly different from that in ordinary leiomyoma, expression of CCL2 was not observed in smooth muscle tumor cells. There were positive correlations between CCL5 and the number of mast cells (r(s)=0.801, P<0.01) and between CCL11 and the number of mast cells (r(s)=0.744, P<0.01) in smooth muscle tumors as well. The vast majority of the mast cells in cellular leiomyoma were CCR3 positive.

CONCLUSIONS

Using the monoclonal anti-mast cell tryptase antibody could detect all mast cells in smooth muscle tumor. The increased intratumoral mast cell counts in cellular leiomyoma might be the result of mast cells recruitment from the peripheral blood rather than local mast cells proliferation. CCL5 and CCL11, which are expressed by smooth muscle tumor cells, are possibly responsible for the recruitment of mast cells in uterine cellular leiomyoma. Whether they combine to CCR3 expressed by mast cells need further study.

Cotyledonoid hydropic intravenous leiomyomatosis: a new variant leiomyoma

AIMS

We present the histopathological findings of a series of six cases of a benign uterine smooth muscle tumour with an unusual growth pattern.

METHODS AND RESULTS

All cases have the appearances of the recently described dissecting (cotyledonoid) leiomyoma. In addition, three of these lesions demonstrate the features of intravenous leiomyomatosis with varying degrees of hydropic degeneration.

CONCLUSIONS

This combination of phenotypes has not previously been described within the literature; therefore we propose that these are classified as examples of 'cotyledonoid hydropic intravenous leiomyomatosis', a new variant of unconventional leiomyoma.

The values of intratumoral mast cell count and Ki-67 immunoreactivity index in differential diagnosis of uterine smooth muscle neoplasms

In this study, the role of the count of intratumoral mast cells was examined and compared with the proliferative activity exhibited by Ki-67 indices in the differential diagnosis of uterine smooth muscle tumors. Sixteen cases of leiomyosarcoma, nine cases of atypical leiomyoma and 16 cases of ordinary leiomyoma were included. The pathological features of the cases were determined by reviewing the archive materials including the patient records and hematoxylin-eosin-stained sections. Toluidine blue stain was used to highlight the intratumoral mast cells and they were counted in at least 40 high power fields. A standard streptavidin-biotin method was applied to the sections to highlight the Ki-67 immunoreactive tumor cell nuclei. These proliferative cells were counted in at least 10 high-power fields. Atypical leiomyomas tended to have a higher quantity of intratumoral mast cells than leiomyosarcomas and ordinary leiomyomas (P = 0.027 and P = 0.021, respectively). Leiomyosarcomas tended to have higher Ki-67 immunoreactivity rates than atypical leiomyomas, although the difference was not statistically significant (P = 0.82). We concluded that the quantity of intratumoral mast cells is useful in the differential diagnosis between leiomyosarcomas and atypical leiomyomas, while the cell proliferation rate expressed by Ki-67 immunoreactivity has a limited value.

Recent advances in the pathology of smooth muscle tumours of the uterus

Smooth muscle tumours of the uterus are common and the majority are benign leiomyomas. However, there are some tumours which exhibit unusual morphological features or growth patterns that cause difficulty in their distinction from malignant neoplasms and those with endometrial stromal differentiation. Such lesions are reviewed in this article with detailed descriptions of their morphology, differential diagnosis and correlation with biological behaviour.

Uterine leiomyomas with Eosinophils: a clinicopathologic study of 3 cases

Although leiomyomas (LMs) of the uterus are common, hematopoietic components within these tumors are not. Lymphoid and other hematopoietic elements have been previously recognized, but eosinophilic infiltrates in LMs have received little attention in the literature. The clinical and pathologic features of 3 cases of uterine LM with eosinophilic infiltration were studied. The patients ranged in age from 35 to 62 years and presented with abdominal and/or pelvic pain and abnormal uterine bleeding. None had peripheral blood eosinophilia or clinical evidence of allergy or parasitic infection. One patient had a benign LM, and the other 2 patients had smooth muscle tumors of uncertain malignant potential. The tumors contained variable numbers of eosinophils and Giemsa stains showed variable numbers of mast cells in addition to the eosinophils. We also performed immunohistochemical and in situ hybridization studies to assess for interleukin-5 (IL-5) and eotaxin in these LMs. There was no consistent association between the presence of eosinophils and either IL-5 or eotaxin in smooth muscle cells, suggesting that mechanisms other than IL-5 or eotaxin production may account for the eosinophilia. Because eosinophils are believed to be involved in wound healing, tissue remodeling, and fibrosis, their presence within LMs may reflect a response to tissue injury produced by the neoplasm rather than intrinsic recruitment by chemotactic factors produced by the smooth muscle cells. Their presence, however, does not appear to have any clinical significance.

The pathology of uterine smooth muscle tumors and mixed endometrial stromal-smooth muscle tumors: a selective review with emphasis on recent advances

This review focuses on the pathology of uterine smooth muscle tumors (SMTs), with a particular emphasis on those studies published in the past 15 years that have expanded our knowledge of these tumors which still present diagnostic challenges for the pathologist. Leiomyoma variants, leiomyosarcoma, SMTs of low or uncertain malignant potential, epithelioid SMTs, SMTs with unusual growth patterns, and mixed endometrial stromal-SMTs are discussed.