Prognostic role of serum p53 antibodies in lung cancer

BACKGROUND

Mutations in the TP53 (Tumour Protein 53) gene can lead to expression of mutant p53 proteins that accumulate in cancer cells and can induce circulating p53 antibodies in cancer patients. Our aim was to evaluate the presence and prognostic role of these antibodies in lung cancer patients and to investigate whether they were related to p53 expression or TP53 mutations in tumour tissues.

METHODS

A total of 201 lung cancer patients were evaluated for p53 antibodies by ELISA (Enzyme-Linked Immunosorbent Assay) and control was obtained from 54 patients with non-malignant disorders; p53 expression was evaluated in 131 of the lung cancer patients by immunohistochemistry and TP53 mutations were then investigated in 53 tumours positively staining for p53 and in 12 tumours without p53 overexpression, whose DNA was available for direct sequencing.

RESULTS

Our results show that 20.4% of cancer patients have positive levels of p53 antibodies, while none of the controls resulted positive. High levels of p53 expression are detected in 57.3% of cases and a significant correlation between serum p53 antibodies and high levels of p53 expression in the corresponding tumours is observed. In non-small cell lung cancer, p53 antibodies are significantly associated with poorly differentiated tumours; furthermore, high levels of p53 expression significantly correlated with squamous cell carcinoma and tumours with highest grade. Survival time of non-small cell lung cancer patients low/negative for serum p53 antibodies was significantly longer compared to patients with positive levels (p = 0.049); in particular, patients with squamous cell carcinoma, but not adenocarcinoma, low/negative for these antibodies show a significant better survival compared to serum-positive patients (p = 0.044).

CONCLUSIONS

In our study, detection of serum p53 antibodies in non-small cell lung cancer patients has been shown to be useful in identifying subsets of patients with poor prognosis. A significant correlation between the presence of serum p53 antibodies in lung cancer patients and p53 overexpression in the corresponding tumours was also observed. We did not find a significant correlation between levels of serum p53 antibodies and TP53 mutations in the corresponding tumours.

The influence of XRCC1 genetic variants on lung cancer susceptibility in Chinese Han population

Growing evidence suggests that genetic variants of X-ray repair cross-complementing group 1 proteins (XRCC1) contribute to genetic effects on the development of lung cancer. This case-control study aims to evaluate the genetic effects of XRCC1 c.482C>T and c.1686C>G single nucleotide polymorphisms (SNPs) on lung cancer susceptibility. 391 lung cancer patients and 398 cancer-free controls were enrolled in this study. The genotypes of c.482C>T and c.1686C>G genetic variants were detected by the created restriction site-polymerase chain reaction (CRS-PCR), PCR-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods. The genetic effects on lung cancer susceptibility were evaluated using association analyses by the unconditional logistic regression model. Our data indicated that there were significant differences in the distribution of allelic and genotypic frequencies between lung cancer patients and cancer-free controls. The XRCC1 c.482C>T and c.1686C>G genetic variants were significantly associated with the susceptibility to lung cancer (for c.482C>T, TT versus (vs.) CC: OR=2.14, 95% CI 1.31-3.48, P=0.002; T vs. C: OR=1.37, 95% CI 1.10-1.69, P=0.004; for c.1686C>G, GG vs. CC: OR=2.53, 95% CI 1.46-4.38, P=0.001; G vs. C: OR=1.33, 95% CI 1.06-1.65, P=0.012). These preliminary results suggested that the XRCC1 c.482C>T and c.1686C>G genetic variants might play genetic effects on the susceptibility to lung cancer in the studied population.