BACTERIAL INFECTION PROFILES AND TUMOR BIOMARKERS IN EGYPTIAN LUNG CANCER PATIENTS

A substantial number of bacterial pathogens have been putatively linked to cancer. In patients with lung cancer, pneumonia is the most important complication and has a high mortality. However, the common pathogens causing pneumonia are not clear. Also there is a need for identification of circulating tumor biomarkers by highly specific and accurate blood tests that can be performed at any medical facility. For these reasons the aim of the present study is identifying the major bacterial species present in sputum of lung cancer patients complaining from pneumonia and to measure the serum level of tumor markers with the assessment of their clinical significance. Methods: 60 patients diagnosed for lung cancer; 44 non small cell lung cancers (NSCLC) & 16 small cell lung cancers (SCLC); as well as 10 control normal healthy adults were included. The sputum of the patients & control were cultured on different culture media for identification of bacteria. Minimum Inhibitory Concentration (MIC) was determined by Microscan. The serums of the same candidates were analyzed for angiopoietin-2 (Ang-2), survivin, Carcinoembryonic antigen (CEA) and Neuron – specific enolase (NSE). Results: E. coli was isolated from 15 sputum samples, α or non hemolytic Streptococci were isolated from 43, Staphylococcus aureus was isolated from 3, K. pneumonia was isolated from 14, P. aeruginosa in 2, other bacteria in 9, Proteus mirabilis in 1, Acintobacter sp. in 2, Enterobacter cloacae in 2, Morganella morganii in 2, Serratia sp. in 1 and Candida in 3. The isolated bacteria showed multidrug resistance to the tested antibiotics.
Serum Ang-2 was significantly higher in SCLC and NSCLC groups as compared to normal group. Mean value of serum survivin was significantly higher in SCLC group as compared to normal and NSCLC groups. While there was no significant increase of serum survivin level in NSCLC group as compared to normal group. Mean value of serum NSE was significantly higher in SCLC group and NSCLC as compared to normal group. Serum NSE was higher in SCLC than in NSCLC group but the difference was not statistically significant. Mean value of serum CEA was significantly higher in SCLC group and NSCLC as compared to normal group. Also the mean value of serum CEA in NSCLC was significantly higher than the mean value of SCLC group. Conclusion: The spectrum of pulmonary infection in patients with lung cancer is wide and depends on the underlying neoplasm and the immunologic deficit or deficits related to it, and to various treatment modalities. The development of drug resistance among common respiratory pathogens is of great concern and underscores the need for the appropriate use of antimicrobial agents and the importance of infection control.
Serum survivin may be a useful marker in diagnosis of SCLC and also for differentiation between SCLC and NSCLC. Serum Ang-2 may be a good marker for lung cancer.