Proteomic Profiling Reveals the Architecture of Granulomatous Lesions Caused by Tuberculosis and Mycobacterium avium Complex Lung Disease.

Tuberculosis (TB) and Mycobacterium avium complex lung disease (MAC-LD) are both characterized pathologically by granuloma lesions, which are typically composed of a necrotic caseum at the center surrounded by fibrotic cells and lymphocytes. Although the histological characterization of TB and MAC-LD granulomas has been well-documented, their molecular signatures have not been fully evaluated. In this research we applied mass spectrometry-based proteomics combined with laser microdissection to investigate the unique protein markers in human mycobacterial granulomatous lesions. Comparing the protein abundance between caseous and cellular sub-compartments of mycobacterial granulomas, we found distinct differences. Proteins involved in cellular metabolism in transcription and translation were abundant in cellular regions, while in caseous regions proteins related to antimicrobial response accumulated. To investigate the determinants of their heterogeneity, we compared the protein abundance in caseous regions between TB and MAC-LD granulomas. We found that several proteins were significantly abundant in the MAC-LD caseum of which proteomic profiles were different from those of the TB caseum. Immunohistochemistry demonstrated that one of these proteins, Angiogenin, specifically localized to the caseous regions of selected MAC-LD granulomas. We also detected peptides derived from mycobacterial proteins in the granulomas of both diseases. This study provides new insights into the architecture of granulomatous lesions in TB and MAC-LD.

Phosphaturic mesenchymal tumor, mixed connective tissue type, non-phosphaturic variant: report of a case and review of 32 cases from the Japanese published work.

Phosphaturic mesenchymal tumor, mixed connective tissue type (PMTMCT) is a rare neoplasm that can cause tumor-induced osteomalacia due to overproduction of a phosphaturic hormone, fibroblast growth factor 23 (FGF23). We report here a case of subcutaneous PMTMCT, non-phosphaturic variant, in the sole. We also review 32 Japanese cases of PMTMCT reported in detail. They occurred in 16 men and 15 women (one was unknown), with ages ranging 20-73 years (median, 48). Tumors were found in soft tissue, bone and sinuses in 17, 11 and four, respectively. A history of long-standing osteomalacia was noted in all cases except two non-phosphaturic variant cases. Serum FGF23 level was elevated in 11 of 12 cases examined. In terms of follow-up information, metastases were found in four patients, and two patients died of disease. In conclusion, PMTMCT is histologically a benign lesion; however, there may be rare metastatic and malignant cases. Wider recognition of the histological features of this unique neoplasm would aid its distinction from the large number of mesenchymal tumors for which it may be mistaken and should enable correct diagnosis of tumors with osteomalacia.

Significance of LRP and PPAR-gamma Expression in Lipomatous Soft Tissue Tumors.

BACKGROUND: Molecular mechanism of differentiation in lipogenic tumor is still unknown in detail. Low-density lipoprotein receptor-related protein (LRP) and peroxisome proliferator-activated receptor gamma (PPAR-gamma), representative regulatory molecules of lipogenic differentiation, have been reported today as multi-functional molecules and to modulate tumorigenesis in various kind of cancer. To date, diagnostic and therapeutic significance of the expression of these molecules in lipogenic tumors are not defined. METHODS: The immunohistochemical expression status of LRP and PPAR-gamma in various grades of 54 lipogenic tumors was analyzed. Correlation between the expression levels and the differentiation of the tumors was confirmed. For statistical analyses, the Kruskal-Wallis test, the Steel-Dwass test and the Mann-Whitney U test were used. RESULTS: LRP and PPAR-gamma expression was detected in 50 (92.6%) and 44 (81.5%) cases, respectively. The expression level in LRP was significantly higher in cases with well differentiated liposarcoma, pleomorphic liposarcoma and dedifferentiated liposarcoma than in lipoma. Compared with lipoma or well differentiated liposarcoma, significant elevation in expression level of PPAR-gamma was confirmed in myxoid liposarcoma, pleomorphic liposarcoma, dedifferentiated liposarcoma and the differentiated area of dedifferentiated liposarcoma. CONCLUSION: The up-regulation of LRP and PPAR-gamma in higher grade cases, i.e. less differentiated tumors than in low grade cases was shown, suggesting the candidate role of these molecules as tumor progression modulators rather than regulatory molecules of differentiation in lipogenic tumors.

Expression of stem cell factor (SCF), a KIT ligand, in gastrointestinal stromal tumors (GISTs): a potential marker for tumor proliferation.

Gastrointestinal stromal tumors (GISTs) show a high incidence of gain-of-function mutations of the c-kit gene, which encodes a receptor tyrosine kinase KIT. This mutation is seen independently of metastasis and/or recurrence of tumors; thus, the factors involved in tumor proliferation rate and malignancy are still not known. Some mesenchymal and epithelial tumors have been reported to co-express KIT and its ligand, stem cell factor (SCF), for autonomous proliferation by the autocrine mechanism. The purpose of this study is to clarify whether GIST cells produce SCF, despite mutated KIT with constitutive activation. Immunohistochemically, we examined the co-expression of KIT and SCF in 36 GIST cases. All cases were found to be KIT-positive, and of these, 21 cases, including four recurrent or metastatic GISTs, showed co-expression of SCF. MIB-1 labeling index was significantly higher, and the average tumor size was larger in SCF-positive cases. By confocal microscopy, KIT was expressed on the cellular membrane, around which SCF was distributed less densely. Western blot analysis revealed that the membrane-bound SCF of 31 kDa was found to be approximately 10 times more abundant than the soluble SCF of 18.5 kDa, suggesting continuous KIT activation. These results indicate that proliferation of GIST cells can be caused not only by the gain-of-function mutation of c-kit, but also by the autocrine mechanism of the SCF/KIT system. Thus, SCF expression would be a useful marker for tumor proliferation.