Abnormalities in the Notch signaling system are considered to play a role in the
tumorigenesis of bronchiogenic
carcinoma. The present study aimed to investigate the expression of Notch3 in adult
lung cancer patients and its role in the pathogenesis of primary bronchiogenic
carcinoma. The expression of the
Notch3 protein in lung
squamous cell carcinoma,
adenocarcinoma,
small cell carcinoma and corresponding non-
tumor tissues was detected by immunohistochemistry. To investigate the expression of Notch3 in
adenocarcinoma tissues, Notch3
mRNA and
protein expression were measured with reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, respectively. It was demonstrated that Notch3 had a stronger positive degree of expression in lung
squamous cell carcinoma and
adenocarcinoma compared with the corresponding non-
tumor tissue (P<0.01). The expression of Notch3 in
small cell carcinoma tissue was lower compared with that of the corresponding non-
tumor tissue (P<0.01). The expression of Notch3 in the
lung adenocarcinoma group was the highest of the three lung
carcinoma groups (P<0.01). RT-PCR revealed that the expression of Notch3
mRNA in the
lung adenocarcinoma group was higher than that of the normal lung group, but there was no statistically significant difference (P=0.05). The expression of
Notch1 protein in the
lung adenocarcinoma group was significantly higher compared with the normal lung group (P<0.01), as shown by western blot analysis. Notch3 may be involved in the pathogenesis of
bronchogenic carcinoma, in particular in the promotion of the
lung cancer oncogene, and a difference in its expression may exist in the various pathological types.