Risk-Predictive and Diagnostic Biomarkers for Colorectal Cancer: A Systematic Review of Studies Using Pre-Diagnostic Blood Samples Collected in Prospective Cohorts and Screening Settings

This systematic review summarizes the evidence for blood-based colorectal cancer biomarkers from studies conducted in pre-diagnostic, asymptomatic settings. Of 1372 studies initially identified, the final selection included 30 studies from prospective cohorts and 23 studies from general screening settings. Overall, the investigations had high quality but considerable variability in data analysis and presentation of results, and few biomarkers demonstrated a clinically relevant discriminatory ability. One of the most promising biomarkers was the anti-p53 antibody, with consistent findings in one screening cohort and in the 3–4 years prior to diagnosis in two prospective cohort studies. Proteins were the most common type of biomarker assessed, particularly carcinoembryonic antigen (CEA) and C-reactive protein (CRP), with modest results. Other potentially promising biomarkers included proteins, such as AREG, MIC-1/GDF15, LRG1 and FGF-21, metabolites and/or metabolite profiles, non-coding RNAs and DNA methylation, as well as re-purposed routine lab tests, such as ferritin and the triglyceride–glucose index. Biomarker panels generally achieved higher discriminatory performance than single markers. In conclusion, this systematic review highlighted anti-p53 antibodies as a promising blood-based biomarker for use in colorectal cancer screening panels, together with other specific proteins. It also underscores the need for validation of promising biomarkers in independent pre-diagnostic settings.

Serum p53 antibodies detection in oral squamous cell carcinoma, oral potentially malignant disorders and healthy indiviuals – a multicentre study

Objective: To detect antibodies against p53 in serum of patients of oral squamous cell carcinoma and oral potentially malignant disorders compared to healthy individuals. Method: The descriptive cross-sectional study was conducted at the departments of Oral and Maxillofacial Surgery, Peshawar Dental College, Peshawar, Khyber College of Dentistry, Peshawar, and the Pakistan Institute of Medical Sciences, Islamabad, Pakistan, from April2016 to March2017, and comprised serum of oral squamous cell carcinoma patients in group A, oral potentially malignant disorder patients in group B and healthy individuals in group C. Serum concentrations of anti-p53 antibodies were determined by enzyme-linked immunosorbent assay. Data was analysed using SPSS 20. Results: Of the180 subjects, there were 60(33.3%) in each of the three groups. Circulating serum p53 antibodies were detected in 59(98.3%) cases in group A, 58(96.6%) in group B and in 20(33.3%) individuals in group C (p=0.001). Conclusion: The expression of circulating p53 antibodies in serum samples of squamous cell carcinoma and oral potentially malignant disorders patients indicates the potential to be a probable candidate for being taken as a diagnostic or prognostic biomarker. Key Words: Tumour suppressor genes, TSGs, Oral squamous cell carcinoma, OSCC, Oral potentially malignant disorders, OPMDs, p53, ELISA. Continuous...

ENZYME-LINKED IMMUNOSORBENT ASSAY DETECTION FOR MALIGNANCY USING ANTI-P53 ANTIBODIES

Tumour protein 53 (p53) plays an important role in the instruction of the cell cycle. In a variety of transformed cell lines, tumour protein is expressed in high amounts, and it is believed to contribute to transformation and malignancy. This research aimed to detect the anti-p53 antibodies in sera of patients with various malignant tumours and to evaluate the sensitivity and specificity of an enzyme-linked immunosorbent assay (ELISA). A case-control study was conducted on samples from 49 patients with various types of malignant tumours at Sultanah Bahiyah Hospital, Alor Setar, Kedah, Malaysia, and 32 healthy control cases with non‐malignant disease collected from Universiti Sains Malaysia clinic, Penang, Malaysia. The antibodies against p53 protein in the serum samples were analysed using the commercial ELISA kit, Calbiochem® p53- ELISAPLUS. The results showed that the rate of anti-p53 antibodies in patients with various malignant tumours was 13 out of 49 (26.5 %), compared with only 2 out of 32 (6.25%) in healthy controls (p < 0.001). The sensitivity of this kit reached 28.6% and the specificity was 93.8%. In conclusion, these results suggest that the anti-p53 antibodies can be detected in different sera of malignant tumour patients and the ELISA kit is highly specific; nevertheless, its discrimination power is not perfect because of its low sensitivity to determine the anti-p53 antibodies.

Comparison of P-53, Ki-67 and Cd-10 Expression Between Fibroadenoma, Benign Phyllodes Tumor and Malignant Phyllodes Tumor

Background: Fibroepithelial tumors of the breast are a heterogeneous group of biphasic lesions comprising of an epithelial component and a quantitatively predominant mesenchymal component. These are classified into two major categories: Fibroadenoma and phyllodes tumor (PT). Phyllodes tumors are classified into benign, borderline and malignant grade categories based on histological parameters. Methods: An analytical-cross sectional study was conducted in the Department of Pathology, Hindu Rao Hospital, Delhi-110007 from November 2016 to December 2018. Total 50 cases were included in the study comprising of 30 cases of fibroadenoma, 15 cases of benign phyllodes tumor and 5 cases of malignant phyllodes tumor. All specimens were fixed in 10% buffered formalin. Tissue were processed and embedded in paraffin. The sections were stained with hematoxylin and eosin (H&E) to study the histopathological section. Immunostaining using CD-10, Ki-67 and p53 antibodies was done in all cases. Result: Among fibroadenoma cases only 3.33% showed positive CD-10 expression and 96.66% were negative. CD-10 expression was positive in 26.67% cases of benign phyllodes while 73.33 showed negative expression. 40% malignant phyllodes cases showed positive CD-10 expression and 60% showed negative CD-10 expression. CD-10 expression was significantly higher in benign phyllodes (p value = 0.019) and malignant phyllodes (p value 0.007) group as compared to fibroadenoma. P-53 expression in epithelium was seen in 56% of fibroadenoma and 26% of benign phyllodes cases, while all cases of malignant phyllodes tumor show negative P-53 expression. The stromal expression of P-53 was significantly higher in malignant phyllodes as compared to fibroadenoma and benign phyllodes tumor. Stromal expression of Ki-67 was significantly higher in malignant phyllodes as compared to benign phyllodes and fibroadenoma. Epithelial expression of Ki-67 was negative in all malignant phyllodes cases while positive epithelial Ki-67 expression was seen in 56% of fibroadenoma and 33% of benign phyllodes tumor. Conclusion: Both Ki-67 and P-53 showed a significantly increasing expression from fibroadenoma to benign phyllodes to malignant phyllodes tumor. The difference in expression of CD-10 was insignificant among fibroadenoma, benign phyllodes and malignant phyllodes tumor.

Preparation and Characterization of Au/NiPc/Anti-p53/BSA Electrode for Application as a p53 Antigen Sensor

While the tumor suppressor protein p53 regulates the cell cycle to prevent cell damage, it also triggers apoptosis and prevents cancer. These inhibitory functions may disappear once the p53 gene is mutated. Under these circumstances, the detection of p53 protein concentrations can have significant clinical applications. In this study, nickel phthalocyanine (NiPc) was coated on a gold electrode to produce a modified Au/NiPc electrode. p53 antibodies were bonded to the Au/NiPc electrode by the Ni+2 ion in NiPc, which can be self-assembled with the imidazole group of the p53 protein. The Au/NiPc/anti-p53 electrode was subsequently dripped with a buffer solution of bovine serum albumin (BSA) to form the Au/NiPc/anti-p53/BSA electrode, which was used for the detection of p53 antigen under 10 mM potassium ferricyanide/potassium ferrocyanide (K3Fe(CN)6/K4Fe(CN)6) solution by cyclic voltammetry and differential pulse voltammetry analyses. The linear detection range and the sensitivity for the p53 antigen were 0.1–500 pg/mL and 60.65 μA/Log (pg/mL)-cm2, respectively, with a detection time of 90–150 s. In addition, Au/NiPc/anti-p53 (100 ng/mL)/BSA electrodes were tested for specificity using glucose, bovine serum albumin, histidine, ascorbic acid, uric acid, prostate-specific antigen, human serum albumin, and human immunoglobulin G. All p-values were <0.0005, indicating an outstanding specificity.

Prognostic value of circulating Bcl-2 and anti-p53 antibodies in patients with breast cancer: A long term follow-up (17.5 years)

BACKGROUND: Apoptosis inhibition is a major tumorigenic factor. Bcl-2 dysregulation and TP53 mutation status, which may correlate with autoantibody generation, contribute to impaired apoptosis. OBJECTIVE: This study aimed to investigate the prognostic value of circulating Bcl-2 and anti-p53 antibodies (p53Abs) in a 17.5-year follow-up of breast cancer patients. We also analyzed the correlations of Bcl-2 and p53Abs with various clinicopathological parameters in order to assess their impact on tumor aggressiveness. METHODS: Serum Bcl-2 and p53Abs levels were analyzed by the enzyme-linked immunosorbent assay (ELISA) in 82 patients with invasive breast cancer and twenty individuals without malignancy. RESULTS: Serum Bcl-2 and p53Abs levels in breast cancer patients were significantly higher than those in controls. Patients with high levels of Bcl-2 (cut-off 200 U/ml) had a poorer prognosis (17.5-year survival) than those with lower Bcl-2 values. In combined analysis the subgroup of patients with elevated p53Abs (cut-off 15 U/ml) and elevated Bcl-2 (cut-offs 124 U/ml and 200 U/ml) had the worse prognosis in 17.5-year survival. In correlation analysis p53Abs and Bcl-2 were associated with unfavorable clinicopathological parameters. CONCLUSIONS: Our results suggest that breast cancer patients with high serum levels of p53Abs and Bcl-2 present an especially unfavorable group in a long follow-up.

Mutant p53 as an Antigen in Cancer Immunotherapy

The p53 tumor suppressor plays a pivotal role in cancer and infectious disease. Many oncology treatments are now calling on immunotherapy approaches, and scores of studies have investigated the role of p53 antibodies in cancer diagnosis and therapy. This review summarizes the current knowledge from the preliminary evidence that suggests a potential role of p53 as an antigen in the adaptive immune response and as a key monitor of the innate immune system, thereby speculating on the idea that mutant p53 antigens serve as a druggable targets in immunotherapy. Except in a few cases, the vast majority of published work on p53 antibodies in cancer patients use wild-type p53 as the antigen to detect these antibodies and it is unclear whether they can recognize p53 mutants carried by cancer patients at all. We envision that an antibody targeting a specific mutant p53 will be effective therapeutically against a cancer carrying the exact same mutant p53. To corroborate such a possibility, a recent study showed that a T cell receptor-like (TCLR) antibody, initially made for a wild-type antigen, was capable of discriminating between mutant p53 and wild-type p53, specifically killing more cancer cells expressing mutant p53 than wild-type p53 in vitro and inhibiting the tumour growth of mice injected with mutant p53 cancer cells than mice with wild-type p53 cancer cells. Thus, novel antibodies targeting mutant p53, but not the wild-type isoform, should be pursued in preclinical and clinical studies.