Background. Emergence of multidrug-resistant tuberculosis (MDR-TB) poses a major challenge to prevailing disease management. MDR-TB arises from mutations in several genes comprising the resistance determining regions, including rpoB, katG and gyrA. Objective. To detect and characterize mutations in rpoB, katG and gyrA. Methods. Thirty selected Mycobacterium tuberculosis isolates from the IDS-PGH were subjected to PCR amplification and sequencing. Sequences were compared to the wild type strain H37Rv. Results. Mutations were detected in codons 512, 513, 516, 522, 526, 531 and 533 of rpoB, codons 280, 281, 315 and 333 of katG, and codons 90 and 94 of gyrA sequences. The most frequently mutating codons for rpoB, katG and gyrA were 531, 315 and 94, respectively. A clustering analysis of the sequences showed occurrence of seven, four and three clusters for the genes rpoB, katG and gyrA, respectively. The eight clusters obtained from the concatenated sequences of the three genes represent the eight potential genotypes of local strains. One cluster represents the wild type strain genotype, another cluster represents the XDR strain genotype, and six clusters represent the MDR strain genotypes. Conclusion. These findings indicate the utility of multiple RDR sequence analysis in both identifying specific drug resistance mutation and genotyping of various M. tuberculosis isolates.
TUBERCULOSIS ; THERAPEUTICS ; THERAPY

Dedifferentiated liposarcoma is a soft tissue sarcoma of adipocytic lineage. Histopathology and immunohistochemistry are essential for diagnosis. A 51-year-old Filipino woman presented with a rapidly enlarging left gluteal tumor. Histopathology revealed a multilobulated tumor having prominent myxoid stroma with numerous stellate-shaped, atypical cells bearing atypical mitotic figures. Other lobules were composed of sheets of pleomorphic cells, with atypical mitotic figures. The tumor stained positively with alcian blue, vimentin, MDM2 and p16 stains. Other immunohistochemical (IHC) studies done (pancytokeratin, CK7, CK 20, CD 34, CEA, desmin, EMA, SMA, S100) showed negative results. After a 2 cm wide excision of the sarcoma, patient was free from local tumor recurrence for 2 months, after which she was lost to follow-up. We report this case and a brief review of the current literature on dedifferentiated liposarcoma.
Liposarcoma ; Immunohistochemistry