Angiomatoid Fibrous Histiocytoma With ALK Expression in an Unusual Location and Age Group.

Angiomatoid fibrous histiocytoma (AFH) is a relatively rare soft tissue tumor of intermediate malignant potential, occurring most commonly in young adults, with a recognized propensity for local recurrence and occasional metastasis. A case of AFH occurring on the finger of a 60-year-old man is described in which the unusual location and age group for this entity raised the original wrong diagnosis of an aneurysmal and cellular fibrous histiocytoma. Further workup demonstrated an EWSR1-CREB1 translocation, confirming the correct diagnosis of AFH. Strong anaplastic lymphoma kinase (ALK) expression using the antibody clone D5F3 was demonstrated in our case on immunohistochemistry, which is in concordance with recent findings of anaplastic lymphoma kinase positivity with this antibody in the majority of AFHs.

Undifferentiated pleomorphic sarcoma with co-existence of KRAS/PIK3CA mutations.

BACKGROUND: Undifferentiated pleomorphic sarcoma (UPS), previously known as malignant fibrous histiocytoma, comprises a series of high-grade soft tissue sarcomas, which fail to exhibit any specific line of differentiation by using currently available ancillary techniques. Studies on gene mutation screening occurring in UPS are rarely conducted. In this study, we described a case of UPS and analyzed its mutation changes. We detected 19 hotspot oncogenes in the case. To the best of our knowledge, this study is the first to use a high-throughput OncoCarta panel 1.0 and MassARRAY system to detect 238 known mutations in 19 hotspot oncogenes in UPS. In this study, our result revealed two missense mutations, namely, KRAS mutation (35G > A, G12D) and PIK3CA mutation (1636C > A, Q546K) in the case.

The ALDH1⁺ subpopulation of the human NMFH-1 cell line exhibits cancer stem-like characteristics.

Cancer stem cells (CSCs) have been reported in many tissues. However, CSCs have yet to be identified in a human malignant fibrous histiocytoma (MFH) cell line. Elevated aldehyde dehydrogenase 1 (ALDH1) has been proposed as a stem cell marker for isolating CSCs from cancer. The aim of the present study was to identify a population with elevated ALDH in the human NMFH-1 cell line. ALDH⁺ and ALDH- cell populations were isolated and compared for CSC characteristics. ALDH enzymatic activity was used as a marker to identify the cells in the NMFH-1 line. Self-renewal, differentiation capacity, and tumorigenicity of the NMFH-1 ALDH⁺ cell population were then examined using a spheroid formation assay and xenograft model in nude mice. Chemoresistance levels, ABCG2 drug transport gene expression, and stem cell-associated gene expression were compared in these NMFH-1 populations. The ALDH⁺ population was better able to form spheres in anchorage-independent serum-starved conditions. Furthermore, the mRNA expression of key stem cell-related genes was enhanced in these cells. Increased expression of the drug transporter gene, ABCG2, was detected. Compared with ALDH-, the ALDH⁺ subpopulation had higher levels of chemoresistance to doxorubicin (DXR) and cisplatin (CDDP). Additionally, the ALDH⁺ cells more efficiently formed tumors when implanted into BALB/c nude mice. ALDH1 may therefore be used as a marker for the isolation of cells that exhibit several characteristics of CSCs from the NMFH-1 cell line. This finding may lead to the development of novel therapies to specifically kill ALDH1⁺ subpopulations (CSCs).

Protein kinase Cδ in tumorigenesis of human malignant fibrous histiocytoma.

Protein kinase Cδ (PKCδ), an isoform of PKC, has been shown to act as a critical mediator of tumor progression and apoptosis; however, its role in musculoskeletal tumors is still unknown. In the current study, we examined the expression of PKCδ in human musculoskeletal tumor tissue samples, and investigated the effects of siRNA downregulation of PKCδ on human malignant fibrous histiocytoma (MFH) cell proliferation, migration, and apoptosis, to elucidate its functional roles in musculoskeletal tumorigenesis. Of note, real-time PCR analysis revealed that mRNA expression of PKCδ in high-grade musculoskeletal MFH tumors was significantly lower than that in benign schwannomas. siRNA downregulation of PKCδ significantly increased human MFH cell proliferation and migration, and markedly suppressed apoptosis. These findings suggest that PKCδ has a negative effect on tumorigenesis and/or acts as a pro-apoptotic kinase in human MFH cells. The data presented here could be applied in the development of new therapeutic avenues, with the elevation of PKCδ expression being one potential strategy to prevent MFH progression. Thus, PKCδ may be a potent therapeutic target for human MFH.

The role of MAPK pathway in bone and soft tissue tumors.

AIM: Expression of mitogen-activated protein kinase (MAPK) signaling and its role in cell proliferation of the bone malignancies, osteosarcoma (OS) and malignant fibrous histiocytoma (MFH) were investigated. MATERIALS AND METHODS: Gene expression and protein levels of RAF1 and MEK1/2 in 6 human sarcoma cell lines and 7 surgically obtained OS specimens were assessed by RT-PCR and immunohistochemistry, respectively. MEK inhibitor, U0126 [1,4-diamino-2,3-dicyano-1,4-bis (2-aminophynyltio) butadiene], was used for cell proliferation assays. RESULTS: RAF1 and MEK 1/2 mRNA was detected in all cell lines and OS specimens. RAF1, MEK 1/2 and p-MEK protein was also expressed in the cells, as was MEK1/2 in OS specimens. Treatment with U0126 resulted in dose- and time-dependent inhibition of cell proliferation and suppression of p-ERK expression, opposite to promotion of p-MEK. CONCLUSION: U0126 blocks MAPK signaling and decreases cell proliferation in OS and MFH. Thus, selective MAPK inhibitors might be therapeutically advantageous in the treatment of bone and soft tissue sarcomas.

Imatinib mesylate inhibits tumorigenicity of malignant fibrous histiocytoma cells in vivo.

BACKGROUND: Malignant fibrous histiocytoma (MFH) is one of the most diffuse and aggressive tumors among soft tissue sarcomas in adults, but still poorly characterized from the molecular viewpoint. MFH cell proliferation is inhibited selectively by imatinib mesylate, a tyrosine kinase inhibitor. The expressions of platelet-derived growth factor receptors (PDGFRs) and c-Kit have been previously examined in MFH cell lines and the inhibitory effect of imatinib mesylate on the MFH cell proliferation was tested. MFH cell lines showed various patterns of PDGFRs and c-Kit expression. Imatinib mesylate inhibited the proliferation of MFH cells that expressed PDGFRs and/or c-Kit. MATERIALS AND METHODS: Four MFH cell lines were used (Nara H, Nara F, GBS-1 and TNMY1). The mRNA expression of PDGFRs and c-Kit was analyzed using RT-PCR; cell proliferation was analyzed using the MTS assay. Immunohistochemistry was used to analyze the inhibitory effect of imatinib mesylate on phosphorylation of PDGFRs and c-Kit in vivo. The Nara H and TNMY1 cell lines were implanted into nude mice and tumor growth was evaluated daily by measuring the two-dimensional diameters of the tumor nodule. RESULTS: PDGFRs and c-Kit were expressed in Nara F, GBS-1 and TNMY1, but not in Nara H cells. Imatinib mesylate inhibited PDGFRs and c-Kit phosphorylation in TNMY1 cells affecting the tumorigenicity, in the control group (139 mm3 SD +/- 1.03) and treatment group (126.2 mm3 SD +/- 1.63) but did not affect the tumorigenicity of Nara H cells. CONCLUSION: Imatinib mesylate reduced in vivo tumor growth of MFH that express PDGFRs and c-Kit associated with phosphorylation suppression.

Characterization of a rat subcutaneous malignant fibrous histiocytoma and its tumor lines, with reference to histiocytic features.

Malignant fibrous histiocytoma (MFH) is regarded as soft tissue-derived undifferentiated pleomorphic sarcoma, of which the histogenesis remains to be proven. To investigate the cellular characteristics, a homotransplantable tumor line (KJ) was established from a spontaneous MFH that developed in the subcutis of an aged F344 rat. KJ tumors have been produced in syngeneic rats by serial subcutaneous implantation of tissue fragments. The original and KJ tumors consisted of oval and fusiform cells arranged in interlacing bundles with fibrous stroma. Occasional giant cells with bizarre nuclei were observed. Enzyme/immunohistochemically, neoplastic cells reacted to ED1 and ED2 (antibodies specific for rat histiocytes/macrophages), and showed a positive reaction to vimentin and lysosomal enzyme markers such as acid phosphatase (ACP) and nonspecific esterase (Non-SE). Electron microscopically, neoplastic cells possessed lysosomal granules in cytoplasm. A cloned cell line (KJ-A) was isolated from a KJ tumor. KJ-A cells showed positive reactions to ED1, ED2, ACP, and Non-SE, and had cytoplasmic lysosomal granules. Tumors induced by KJ-A cells exhibited histologic and enzyme/immunohistochemical findings similar to those of KJ tumors. Lipopolysaccharide (LPS) treatment increased the number of ED1-positive cells and the expression of tumor necrosis factor-alpha mRNA by reverse transcription-polymerase chain reaction. Collectively, it is likely that rat MFH cells originally possess histiocyte/macrophage-like features that may be enhanced by LPS. Because tumor lines are useful for in vivo and in vitro studies concerning different characteristics of the original neoplasms. KJ and KJ-A should prove useful for studies concerning the morphogenesis of MFH.

iNOS-dependent DNA damage in patients with malignant fibrous histiocytoma in relation to prognosis.

Malignant fibrous histiocytoma (MFH) is one of the most common soft tissue sarcomas. MFH has been proposed to be a lesion accompanied with inflammatory responses. During chronic inflammation, reactive nitrogen and oxygen species generated from inflammatory cells are considered to participate in carcinogenesis by causing DNA damage. 8-nitroguanine is a mutagenic nitrative DNA lesion formed during chronic inflammation. We examined whether nitrative DNA damage is related to the prognosis of MFH patients. We performed immunohistochemical analyses to examine the distribution of DNA damage and the expression of inflammation-related molecules including inducible nitric oxide synthase (iNOS), nuclear factor-kappaB (NF-kappaB), and cyclooxygenase-2 (COX-2) in clinical specimens from 25 patients with MFH. We also analyzed the correlation of DNA damage or the expression of these genes with the prognosis of MFH patients. Immunohistochemical staining revealed that the formation of 8-nitroguanine and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), an oxidative DNA lesion, occurred to a much greater extent in MFH tissue specimens from deceased patients than in live patients. iNOS, NF-kappaB and COX-2 were colocalized with 8-nitroguanine in MFH tissues. It is noteworthy that the statistical analysis using the Kaplan-Meier method demonstrated strong 8-nitroguanine staining to be associated with a poor prognosis. In conclusion, 8-nitroguanine appears to participate in not only the initiation and promotion of MFH, but also in the progression of MFH, and could therefore be used as a promising biomarker to evaluate the prognosis of cancer patients.