Detection of circulating anti-p53 antibodies in patients with colorectal carcinoma and the antibody's relation to clinical factors

Serum p53 antibody as tumor marker for follow-up of colorectal cancer after curative resection

BACKGROUND

No large-scale studies have examined the use of serial measurements of serum p53 antibodies (s-p53Abs) combined with carcinoembryonic antigen (CEA) measurements during the follow-up of colorectal cancer (CRC) patients after curative resection.

METHODS

A highly specific enzyme-linked immunosorbent assay was used to analyze s-p53Abs levels in 305 CRC patients before and after curative resection at a single institution. Agreement between recurrence and serial s-p53Ab and CEA measurements was evaluated by diagnostic accuracy odds ratio (DOR), kappa, and area under receiver operating characteristic curve (AUC).

RESULTS

Among 305 patients, 76 (25%) patients had disease recurrence during follow-up. None of the 168 s-p53Ab seronegative patients (s-p53Ab < 10 U/microL) without recurrence had an abnormal s-p53Ab test during follow-up. Among the remaining low-level (10 U/microL <or= s-p53Ab <or= 76 U/microL, n = 103) and high-level (s-p53Ab titer > 76 U/microL, n = 34) seropositive patients, recurrence defined by s-p53Ab tests resulted in a DOR of 4.3 and infinity, a kappa of 0.35 and 1.00, and an AUC of 0.633 [95% confidence interval (CI), 0.495 to 0.772; P = 0.047], and 1.0 (95% CI, 1.000 to 1.000; P < 0.0001), respectively. Recurrence defined by CEA tests had an AUC of 0.781 (95% CI, 0.654 to 0.909) for low-level and 0.796 (95% CI, 0.611 to 0.982) for high-level seropositive patients.

CONCLUSIONS

Agreement between clinical recurrence and serial s-p53Ab test was dependent upon preoperative s-p53Ab level. Serial s-p53Ab testing outperformed CEA testing when predicting clinical recurrence in colorectal cancer patients with an abnormal preoperative s-p53Ab level.

Anti-p53 autoantibody in colorectal cancer: prognostic significance in long-term follow-up

BACKGROUND

The prognostic significance of anti-53 autoantibody in colorectal cancer (CRC) patients is unclear due to measurement of overall rather than disease-specific survival and generally short follow-up periods in many studies. We aim to investigate prognostic significance of anti-p53 auto-antibodies in a study with long-term follow-up (minimum 5 years).

METHODS

ELISA for anti-p53 autoantibody was assayed in serum from 92 patients with CRC and 28 controls.

RESULTS

Anti-p53 autoantibody was found in 20 patients (21.7%) and none of the controls. No difference in Dukes' (A/B vs. C/D), Stage (I/II vs. III/IV), T1/2 vs. T3/4, N0 vs. N1/2, M0 vs. M1, poor vs. well/moderate differentiation and proximal vs. distal CRC was observed. Median overall survival was 62 months and median disease-specific survival was 73 months. Dukes' C/D, Stage III/IV, N1/2 and M1 were associated with poor disease-specific survival in univariate analysis. Stage III/IV was an independent prognostic factor in overall and disease-free survival in multivariate analysis. Anti-p53 autoantibody sero-positivity did not influence overall (p = 0.980) or disease-specific survival (p = 0.874). Median overall survival in anti-p53 autoantibody positive patients was 62 months vs. 60 months in anti-53 autoantibody negative patients. Median disease-specific survival in anti-p53 autoantibody positive patients was 73 months vs. 82 months.

CONCLUSION

Anti-p53 autoantibody is not related to clinical parameters of CRC and has no prognostic significance in long-term follow-up.

The clinical significance of autoantibodies in gastrointestinal malignancies: an overview

Autoimmunity can be associated with cancer and one of the forms of its expression is the development of antibodies to autologous cellular antigens. The types of cellular proteins which induce autoantibody responses in gastrointestinal malignancies are quite varied and include cellular proteins encoded by mutated normal genes (p53), cellular proteins that are overexpressed and/or aberrantly expressed in malignant tissues (carcinoembryonic antigen), inhibitors of apoptosis (survivin and livin), major components of mucus (mucins), surface receptors of apoptosis (Fas) and nuclear-restricted proteins (double-stranded DNA, single-stranded DNA and Sm family proteins). In the past few years, due to the great clinical interest and the advancement in detection techniques, the above list has grown significantly and a large number of cancer-related antigens, which trigger a specific humoral immune response to the host, have also been identified. The authors review the autoantibodies associated with gastrointestinal malignancies and their clinical implications.

Pre- and post-operative sequential changes of serum P53 antibody, carcinoembryonic antigen and carbohydrate antigen 19-9 in patients with colorectal cancer

AIM: To investigate the value of sequential change of pre- and post-operative serum P53 antibodies, carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) in patients with colorectal cancer.

METHODS: A total of 132 patients with colorectal cancer and 36 ones with benign lesions (as controls) were included in this prospective study. The blood samples were collected 1 h before operation and 30 d postoperatively. The presence of serum P53 antibody was determined by enzyme-linked immunosorbent assay (ELISA). The levels of serum CEA and CA19-9 were detected using radioimmunoassay (RIA).

RESULTS: The positive rate of serum P53 antibodies in patients with colorectal cancer were significantly higher than that in ones with benign disease (χ² = 18.11, P < 0.0001). Thirty-nine (74%) of P53 seropositive patients showed negative conversion 1 mo after operation, including 3 cases (33%) in palliative surgery group and 36 cases (82%) in radical operation group (χ² = 9.04, P = 0.0026). Thirteen (54%) of CEA seropositive patients showed negative conversion 1 mo after operation, including 2 cases (18%) in palliative surgery group and 11 cases (85%) in radical operation group (χ² = 10.60, P = 0.0011). Seven (41%) of CA19-9 seropositive patients showed negative conversion 1 mo after operation, including 2 cases (20%) in palliative surgery group and 5 cases (71%) in radical operation group (χ² = 4.50, P = 0.034).

CONCLUSION: Monitoring of sequential changes of pre- and post-operative serum P53 antibodies, CEA and CA19-9 in patients with colorectal cancer can help to evaluate responses to treatment, judge prognosis and guide the comprehensive treatment after operation.

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Humoral response to p53 in human colorectal tumors: a prospective study of 1,209 patients

p53 Antibodies (p53-Abs) have been detected in the serum of a proportion of colorectal cancer (CRC) patients. It is not yet known at which stage during colorectal tumor progression p53-Abs appear in the serum. The utility of these antibodies as markers for CRC prognosis remains to be clarified. Using a quantitative enzyme-linked immunosorbent assay, we analyzed serum samples from 998 CRC patients and from 211 patients with polyp. Levels of p53-Abs were defined as negative (<10 U/microL), low (10-76 U/microL) and high (>76 U/microL). Overall, 13.0% of CRC patients and less than 1% of polyp patients had increased serum p53-Ab levels. High p53-Ab levels were only seen in patients with invasive carcinomas. The parameters that were significantly and independently associated with a greater frequency of high p53-Ab levels were the left colon (odds ratio [OR] = 3.4; 95% CI = 1.1-10.5), the rectum (OR = 2.9; 95% CI, 1.0-8.8) and advanced lymph node metastasis (OR = 4.6; 95% CI, 2.2-9.6). In univariate analysis, patients with high p53-Ab levels had a shorter survival times than did those without (p = 0.007). However, the significant effect disappeared in a Cox regression model adjusting for sex, age, tumor location, carcinoembryonic antigen levels, gross findings, histologic grade, mucin production and TNM stage. Thus, autoantibodies against p53 occur with tumor progression in multistep colorectal carcinogenesis and increase with advanced node metastasis. Furthermore, the seemingly adverse effect of high p53-Ab levels on the survival of CRC patients may be explained by other prognostic factors.

The p53 tumor suppressor gene: from molecular biology to clinical investigation

The tumor suppressor p53 is a phosphoprotein barely detectable in the nucleus of normal cells. Upon cellular stress, particularly that induced by DNA damage, p53 can arrest cell cycle progression, thus allowing the DNA to be repaired; or it can lead to apoptosis. These functions are achieved, in part, by the transactivational properties of p53, which activate a series of genes involved in cell cycle regulation. In cancer cells bearing a mutant p53, this protein is no longer able to control cell proliferation, resulting in inefficient DNA repair and the emergence of genetically unstable cells. The most common changes of p53 in human cancers are point missense mutations within the coding sequences of the gene. Such mutations are found in all major histogenetic groups, including cancers of the colon (60%), stomach (60%), breast (20%), lung (70%), brain (40%), and esophagus (60%). It is estimated that p53 mutations are the most frequent genetic event in human cancers, accounting for more than 50% of cases. One of the most striking features of the inactive mutant p53 protein is its increased stability (half-life of several hours, compared to 20 min for wild-type p53) and its accumulation in the nucleus of neoplastic cells. Therefore, positive immunostaining is indicative of abnormalities of the p53 gene and its product. Several studies have shown that p53 mutations are associated with short survival in colorectal cancer, but the use of p53 as a tumoral marker is still a matter of debate.

[Serum p53 antibody assay: evaluation in colorectal cancer]

INTRODUCTION

Alterations of the tumor suppressor gene p53 and its protein synthesis is the most commonly observed genetic feature in human cancers. Direct diagnosis of the gene mutation using sequencing is the gold standard method. However, it requires advanced technology and is only performed in specialized research units.

CURRENT KNOWLEDGE AND KEY POINTS

Demonstration of intratumoral p53 protein accumulation using immunohistochemistry is a routine diagnostic technique. Serum detection of p53 antibodies using ELISA has been recently developed. It is an easily feasible and reproducible method for the diagnosis of p53 alterations due to self-immunization in some patients in response to intratumoral p53 protein overexpression. This phenomenon is inconstant (about one-third of the patients with a p53 gene mutation produce antibodies) and its mechanism is unclear. p53 Antibodies are found in 25% of the patients with colorectal cancer, independently of traditional tumor markers (carcinoembryonic antigen and carbohydrate antigen 19.9). The presence of these antibodies is not linked to the tumor stage. Since their ratios vary during the treatment, they might constitute a new tumor marker.

FUTURE PROSPECTS AND PROJECTS

Early appearance of p53 serum antibodies during tumor development should make them useful for the detection of malignant transformation in patients with preneoplastic disease such as ulcerous colititis. Whether the presence of p53 antibodies in colorectal cancer patients has a prognostic significance requires further assessment.

Association of serum antibodies against p53 protein with poor survival in patients with Zollinger-Ellison syndrome

BACKGROUND & AIMS

Long-term survival of patients with Zollinger-Ellison syndrome (ZES) is largely determined by the presence or absence of liver metastases. However, because of the lack of precision of these criteria, development of further indicators is still required. Recent evidence showing that autoantibodies directed against the p53 protein could predict poor survival for some types of cancers prompted us to investigate the presence of such antibodies in sera from patients with ZES and their potential value as survival indicator.

METHODS

Anti-p53 antibodies were detected in the sera of 44 consecutive patients with ZES using both an enzyme-linked immunosorbent assay (ELISA) and Western blotting. The mean follow-up of these patients was 92 months.

RESULTS

Anti-p53 antibodies were detected in 7 of the patients with ZES (16%) by both ELISA and Western blotting. Univariate and multivariate analyses showed that the presence of anti-p53 antibodies (P = 0.0009 and P = 0.017, respectively) and liver metastases (P = 0.0009 and P = 0.012, respectively) was independently associated with shorter survival.

CONCLUSIONS

These results suggest that anti-p53 antibodies are an indicator of survival and could be used in combination with staging to determine which patients with ZES have poor prognoses and therefore require reinforced therapy.