ObjectiveThe aim of this study was to examine serum prealbumin (PA) levels in patients with tuberculosis and lung cancer, and to evaluate the correlations of serum PA levels with clinicopathological characteristics.MethodTotal 760 patients were included in the study: 320 patients with tuberculosis, 320 patients with lung cancer, and 120 healthy subjects. Serum PA was detected using a biochemical analyzer to determine the value of serum PA in the diagnosis and therapeutic response of tuberculosis.ResultsCompared to lung cancer and healthy individuals, TB patients were more frequent in suffering from low serum PA (75.0% vs.30.9% vs.6.7%,P<0.01), and the serum PA levels of TB patients were significantly reduced (137.5±42.4 mg/L vs. 183.5±49.1 mg/L vs. 240.0±43.9 mg/L, P<0.01). Among various clinical characteristics, type (with pleuritis), age (≥60), ESR (>20 mm/h) and smoking status (≥20 pack×years) were associated with low serum PA levels of TB patients, while ECOG performance status (≥2) was associated with low serum PA levels of lung cancer patients. The change of serum PA levels was in accordance with the therapeutic effects of anti-TB drugs, which might present a valuable and objective indicator for monitoring the therapeutic effects of TB drugs on TB patients.ConclusionLow serum prealbumin levels are very common in TB patients and can be served as a potential indicator for differential diagnosis of lung cancer and monitoring the therapeutic effects of TB drugs.

Multi-drug resistance leads to the failure of chemotherapy for cancers. Our previous study showed that overexpression of CA916798 led to multi-drug resistance. However, the underlying mechanisms remain unknown. In the current study, we observed that the levels of phosphorylated AKT, phosphorylated mTOR and CA916798 all increased in the drug resistant human adenocarcinoma samples and paralleled with the change of drug resistance. The results of immunofluorescence and Co-IP indicated that the positive correlation of CA916798 expression with AKT1 activation might be associated with drug resistance of lung adenocarcinoma. Furthermore, AKT1 stimulated CA916798 expression through mTOR pathway in both A549 and A549/CDDP cell lines, which was also observed in the xenografted tumor in nude mice. The results showed that CA916798 located in the downstream of PI3K/AKT/mTOR pathway. Inhibition of PI3K by LY294002 could efficiently reduce CA916798 expression and tumor size in vivo as well. Additionally, LY294002 combined with rapamycin inhibited CA916798 expression and tumor size stronger than LY294002 alone. Our findings may also provide a new explanation for synergistic anti-tumor effects of PI3K and mTORC1 inhibitors.