Expression of inflammatory proteins STAT & NFĸB for phenotypic diagnosis of gall bladder cancer: A pilot study

Abstract

Background & objectives Gallbladder cancer (GBC) has a low overall survival rate due to late detection and poor prognosis. Chronic inflammation contributes to malignant conversion and metastasis in GBC. Expression of inflammatory proteins, such as signal transducer and activator of transcription factor (STAT) and nuclear factor kappa B (NFĸB) proteins, for diagnosis through immunohistochemistry (IHC) is a promising area of research; however, diagnosis of GBC through IHC-based methods is still in its infancy. So, the present pilot study explores the use of STAT proteins (STAT 3 and 6) and NFĸB as diagnostic biomarkers for GBC. Methods Histologically confirmed cases of GBC (n=13) and cholelithiasis (n=23) as controls, were recruited. IHC was performed for protein expression of STAT3, STAT6, and NFĸB. Subgrouping into high and low expression was performed based on the receiver operating curve (ROC) analysis. Diagnostic utility and its association with the aggressiveness of cancer were assessed. Results The mean age of GBC and cholelithiasis patients was 50.84±14.5 and 44.0±11.9 years, respectively. Liver infiltration and metastasis were observed in 61 per cent and 69 per cent of the patients, respectively. STAT3, STAT6, and NFĸB expressions were significantly higher in GBC as compared to cholelithiasis. Sensitivity and specificity for STAT3 and STAT6 were 91, 47 and 75, 39 per cent, respectively. STAT6 expression was associated with lymph node involvement. Whereas, both STAT3 and STAT6 expressions were associated with Liver infiltration. Interpretation & conclusions This pilot study demonstrated STAT3 and STAT6 as sensitive and specific molecular biomarkers for diagnosing and assessing the aggressiveness of GBC. These may be used as an adjunct to the diagnosis of GBC after validation on a larger sample size.

Keywords: Chronic cholecystitis; NFĸB; STAT; gall bladder cancer (GBC); inflammatory proteins.

Fig. 1.

Immunohistochemistry of STAT and NFĸB in GBC and cholelithiasis. Representative immunohistochemistry (IHC) staining images illustrating the expression of STAT3, STAT6, and NFĸB in cholelithiasis and gallbladder adenocarcinoma. Panels (A), (C), and (E) show nuclear and cytoplasmic expression of STAT3, STAT6, and NFĸB in cholelithiasis, while panels (B), (D), and (F) depict the expression in gallbladder adenocarcinoma. Images (A), (C), (D), (E), and (F) are captured at 20× magnification, whereas image (B) is captured at 40× magnification. Additionally, panels (G) and (H) present representative images of STAT6 expression in gallbladder adenocarcinoma at 40× and 100× magnification, respectively, highlighting tumor cells exhibiting predominantly cytoplasmic and focal nuclear immunopositivity for STAT6.

Fig. 2.

Receiver operating characteristics curve for STAT and NFĸB. ROC curve for STAT3, STAT6 and NFĸB with corresponding AUC (area under curve) value.