Objective: To develop a system for the molecular diagnosis of tuberculosis by polymerase chain reaction (PCR), constructing primers based on the difference in gene organization of the intergenic region of phospholipase C (plcB-plcC region), which differentiates Mycobacterium tuberculosis from other mycobacteria. Methods: A PCR product of the expected size (432 bp) was obtained from M. tuberculosis and M. africanum only. A total of 33 mycobacterial isolates and 273 clinical samples from patients suspected of having tuberculosis were examined. These were used in the comparative study of the PCR technique versus culture. Results: For PCR versus culture, the data showed 93.8% accuracy (p < 0.0001), 93.1% sensitivity (CI: 88.7-96.0), and 96.4% specificity (CI: 96.1-99.4). The Kappa value (0.82) shows that there was a near-perfect concordance between the two tests. Conclusion: The use of the plcB-plcC region in PCR amplification was found to be an important and reliable tool for the specific diagnosis of tuberculosis in the samples analyzed.

Keywords: Polymerase chain reaction; Diagnosis; Tuberculosis; Mycobacterium tuberculosis

Objective: The objective of this study was to identify the clinical and pathological factors that can influence the prognosis of breast cancer patients with clinical symptoms of malignant pleural effusion. Methods: This was a clinical cohort study, in which we analyzed the medical charts of patients diagnosed with malignant pleural effusion between 2006 and 2010. By examining the charts, we identified the female patients with a history of breast cancer. For those patients, we collected pathology data related to the primary tumor and cytopathology data related to the pleural metastasis. Results: We evaluated 145 patients, 87 (60%) of whom had tested positive for malignant cells in the pleural fluid. Ductal histology was observed in 119 (82%). The triple-negative breast cancer phenotype was seen in 25 cases (17%). Those patients had the worst prognosis (with a sharp decline in the survival curve), and 20 of the 25 (80%) died during the follow-up period (through June of 2011). The mean survival after the identification of malignant pleural effusion was 6 months. Conclusions: In patients with triple-negative breast cancer who test positive for malignant cells in the pleural fluid, the prognosis is poor and survival is reduced.

Keywords: Pleural effusion, malignant/mortality; Breast neoplasms/mortality; Breast neoplasms/genetics.