Background: Tumor susceptibility gene 101 (TSG101) is identified in a random mutagenesis screening for potential tumor suppressors in NIH 3T3 cells. This study is designed to investigate the relationship between sex, age, tumor size, histological type, differentiation, clinical stage and lymphnode metastasis with the expression of TSG101 in human squamous cell carcinoma and adenocarcinoma of the lung, and to analyze whether there is relativity between TSG101, P21 and P300/CBP.
Methods: Immunohistochemical method (SP method) was adopted to detect the expression of TSG101, P21 and P300/CBP proteins in cancer tissues and neighboring noncancerous tissues of 79 cases of human squamous cell carcinoma and adenocarcinoma of the lung. Western blot method was adopted to detect the expression of TSG101 protein in 26 tumor tissues and normal tissues adjacent to cancer.
Results: The expression rate of TSG101, P21 and P300/CBP was 59.49% (47/79), 60.76% (48/79) and 56.96% (45/79) respectively. There was no relationship between TSG101 expression and age, sex, tumor size, histological type and P-TNM stage (P > 0.05); otherwise, there was closely relationship between TSG101 expression and cellular differentiation, lymphnode metastasis (P < 0.05). The positive rate of P21 and P300/CBP protein was correlated with the cellular differentiation, lymphnode metastasis and P-TNM stage (P < 0.05). The expression rate of TSG101, P21 and P300/CBP in well and moderately differentiated cells was significantly higher than that in poorly differentiated cells (P < 0.05), and the expression rate of TSG101, P21 and P300/CBP in patients without lymphnode metastasis was significantly higher than that in those with lymph node metastasis (P < 0.01). In the group with lymphnode metastasis and the group without lymphnode metastasis, the positive rate of TSG101 was 48.89% and 73.53% respectively. There were significant differences (P < 0.05) of the expression of TSG101 between the two groups, as well as P21 and P300/CBP. The expression level of TSG101 was positively correlated with P21 (r=0.710) and P300/CBP (r=0.689). The expression of TSG101 protein in tumor tissues was significantly lower than that in the neighboring noncancerous tissue.
Conclusions: The expression of TSG101, P21 and P300/CBP protein might be associated with lung cancer differentiation and metastasis, the expression of them is positively correlated with each other, hence they can be used as valuable biomarkers to evaluate lung cancer metastasis.