Study on the relationship between Mycobacterium tuberculosis L infection and lung cancer.

Objective:To explore the relationship between Mycobacterium tuberculosis L(MTB-L)infection and tumorigenesis of lung cancer. Methods:One hundred and sixty seven patients with lung cancer, 65 patients with tuberculosis, 60 non-cancer and non-tuberculosis patients as control group were included in the study. MTB-L in surgically resected specimens were detected by Intensified Kinyoun’s(IK)staining and MTB was detected by Ziehl-Neelsen staining. In situ hybridization(ISH)technique was used to determine the MPB64 gene’s expressions in nucleus of lung cancer cells. MTB and MTB-L in some specimens were cultured. SPSS 13.0 software was used for statistical analysis. The positive rates between groups were compared with chi-square test. Results:The positive rate of MTB-L in lung cancer patients was 67.1%(112/167)and the positive rate of MTB was 4.2%(7/167), and the difference was significant between the two groups(P0.05). The positive rate of MTB-L in tuberculosis group (90.8%,59/65)was significantly different compared with lung cancer group(P0.05)and control group (1.7%, 1/60)(P0.05). There was significant difference in MPB64 gene expression in cell nucleus between lung cancer group and tuberculosis group[80.2%(134/167)vs 100%(65/65),P0.05]and between lung cancer group and control group[80.2%(134/167)vs 3.3%(2/60), P0.05]. MTB-L level and MPB64 gene expression had no significant difference between lung cancer tissues with various histological classifications, pathological grade, clinical sta-ging, and lymph node metastasis (all P0.05 for MTB-L and all P0.05 for MPB64). There was no significant difference in MTB-L level and MPB64 gene expression between the patients with and without tuberculosis history (all P0.05). Twenty seven strains of human type MTB-L (57.4%)and 18(66.7%)strains come back to the ancestors MTB were detected out of 47 lung cancer specimens, and the difference was significant(P0.05). Conclusion:MTB-L is the primary type of MTB existing in the lung cancer tissues. MPB64 is highly expressed in the nucleus of lung cancer cells. MTB-L and MPB64 have no correlation with pathological features and tuberculosis history.