Circulating antibodies to p16 protein-derived peptides in breast cancer

Autoantibodies in cancer: a systematic review of their clinical role in the most prevalent cancers

Although blood autoantibodies were initially associated with autoimmune diseases, multiple evidence have been accumulated showing their presence in many types of cancer. This has opened their use in clinics, since cancer autoantibodies might be useful for early detection, prognosis, and monitoring of cancer patients. In this review, we discuss the different techniques available for their discovery and validation. Additionally, we discuss here in detail those autoantibody panels verified in at least two different reports that should be more likely to be specific of each of the four most incident cancers. We also report the recent developed kits for breast and lung cancer detection mostly based on autoantibodies and the identification of novel therapeutic targets because of the screening of the cancer humoral immune response. Finally, we discuss unsolved issues that still need to be addressed for the implementation of cancer autoantibodies in clinical routine for cancer diagnosis, prognosis, and/or monitoring.

P16 Expression in Human Breast Carcinoma and its Relationship to Clinicopathological Parameters

Background

p16 is a cyclin-dependent kinase inhibitor and a cardinal regulator of the cell cycle. The relationship between p16 overexpression and poor prognosis of breast cancer has been reported in some studies. This study aimed to evaluate p16 expression in breast cancer in comparison to normal breast tissue and determine the association between p16 expression and clinicopathological parameters in breast cancer.

Materials and Methods

Paraffin blocks of 110 samples were studied. These included 40 invasive breast carcinoma (tumor group) and normal tissue adjacent to the tumor (tumor control), as well as 30 normal mammoplasty specimens (normal control). Samples were from the pathology archive of Alzahra Hospital, Isfahan, Iran, from 2016 to 2020. p16 expression was studied and compared in these three groups using the immunohistochemistry technique. Moreover, the relationship between p16 expression and age, tumor size, carcinoma subtype, tumor grade, and lymph node involvement was investigated in the tumor group. SPSS version 16 was used to analyze data.

Results

p16 expression showed a significant difference between the tumor group and the two control groups with a significantly higher expression in the tumor group. There was a significant direct relationship between the intensity of p16 expression and the number of involved lymph nodes (P < 0.001). No significant relationship was detected between p16 expression and other clinicopathological factors.

Conclusion

p16 seems to have a rather significant expression in breast cancer in comparison to normal breast parenchyma. However, among clinicopathological parameters, we found only a direct relationship between lymph node involvement and intensity of p16 expression.

Can serum autoantibodies be a potential early detection biomarker for breast cancer in women? A diagnostic test accuracy review and meta-analysis

BACKGROUND

The increasing incidence of breast cancer necessitates the need to explore alternate screening strategies that circumvent the setbacks of conventional techniques especially among population that report earlier age at diagnosis. Serum autoantibodies is one such potential area of interest. However, their ubiquitous presence across cancer types limits its applicability to any one specific type of cancer. This review was therefore carried out to explore and consolidate available evidence on autoantibodies for early detection of breast cancer and to identify those that demonstrated a higher sensitivity.

METHODS

A diagnostic test accuracy (DTA) review was carried out to ascertain serum autoantibodies that could be used for early detection of breast cancer among women. All relevant articles that investigated the role of autoantibodies in early detection of breast cancer were included for the review. MEDLINE, Scopus, ProQuest, Ovid SP, and Cochrane Library were searched extensively for eligible studies. Quality of the included studies was assessed using Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 tool. RevMan 5.3 was used for exploratory and MetaDTA 2019 for hierarchical analyses. The review helped identify the most frequently investigated autoantibodies and a meta-analysis further consolidated the findings.

RESULTS

A total of 53 articles were included for the final analysis that reported over a 100 autoantibodies that were studied for early detection of breast cancer in women. P53, MUC1, HER2, HSP60, P16, Cyclin B1, and c-Myc were the most frequently investigated autoantibodies. Of these P53, MUC1, HER2, and HSP60 exhibited higher summary sensitivity measures. While the individual pooled sensitivity estimates ranged between 10 and 56%, the panel sensitivity values reported across studies were higher with an estimated range of 60-87%.

CONCLUSION

Findings from the review indicate a higher sensitivity for an autoantibody panel in comparison to individual assays. A panel comprising of P53, MUC1, HER2, and HSP60 autoantibodies has the potential to be investigated as an early detection biomarker for breast cancer.

Detection of Circulating Antibodies to p16 Protein-Derived Peptides in Hepatocellular Carcinoma

OBJECTIVE

This study aimed at confirming the alteration of circulating anti-p16 immunoglobulin G (IgG) levels in hepatocellular carcinoma (HCC).

METHODS

An in-house-developed enzyme-linked immunosorbent assay was used for determining plasma IgG antibodies against p16-derived antigens in 122 HCC patients and 134 healthy controls.

RESULTS

Plasma anti-p16 IgG levels were significantly higher in HCC patients than in the controls (Z = 3.51, P = 0.0004), with no difference between males and females. A trend of increasing plasma anti-p16 IgG levels was associated with increasing HCC stage, with group 3 patients having the highest anti-p16 IgG levels (Z = 3.38, P = 0.0008). Group 3 exhibited the best sensitivity (19.6%) and specificity (95%) for plasma anti-p16 IgG detection, with an area under the receiver operating characteristic curve of 0.659 (95% confidence interval, 0.564-0.754).

CONCLUSION

Circulating IgG antibody to p16 protein might be a useful biomarker for HCC prognosis assessment rather than for early malignancy diagnosis.

Identification of novel autoantibody signatures and evaluation of a panel of autoantibodies in breast cancer

Tumor-associated autoantibodies (TAAb) could be serological tumor markers. This study aims to discover novel TAAb signatures for breast cancer (BC) detection. The protein microarray was used to identify candidate TAAb, which were further validated in 1197 sera from BC, benign breast diseases (BD), and healthy controls (HC) by enzyme-linked immunosorbent assay. In addition, 319 preoperative and postoperative sera were evaluated. A panel was determined using four different classifiers. Twelve TAAb were identified with frequencies of 15.8%-59.2%; their levels were significantly decreased in postoperative sera compared to those in preoperative sera (P < .05). A panel with six TAAb was developed and evaluated. The area under the curve (AUC) was 0.879 (74.3% sensitivity, 91.9% specificity) and 0.865 (69.7% sensitivity, 91.7% specificity) for distinguishing BC from HC in the training set and test set, respectively. The panel had an AUC of .884 (71.2% sensitivity, 90.5% specificity) for discriminating BC from BD. For identifying BC from all controls (HC+BD), the AUC was .916 (78.9% sensitivity, 90.2% specificity). The AUC of the panel was .920 and .934 for distinguishing stage I-II and age < 50 BC from HC, respectively. These identified TAAb have the potential to provide a non-invasive approach to detect BC.

Further Study of Circulating Antibodies to P16, CD25 and FOXP3 in Hepatocellular Carcinoma

Purpose

It has been reported that circulating levels of IgG antibodies against p16, CD25 and FOXP3 proteins were significantly changed in patients with lung cancer, breast cancer and esophageal cancer. However, different peptide fragments appear to trigger different immune responses. This work aimed to analyze the alteration of plasma IgG for p16-derived peptide antigen called p16a, CD25-derived peptide antigen called CD25a and a FOXP3-derived antigen in hepatocellular carcinoma (HCC).

Patients and methods

An enzyme-linked immunosorbent assay (ELISA) was developed in-house to detect plasma IgG to p16a, CD25a and FOXP3 in 119 patients with HCC and 132 control subjects.

Results

Circulating levels of IgG antibodies for all three peptide antigens were significantly higher in HCC patients than control subjects (P<0.001 for all 3 assays); male patients mainly contributed to increase (P<0.01 for all 3 assays). Further analysis showed that plasma anti-p16a, anti-CD25a and anti-FOXP3 IgG levels were increased mainly in patients with intermediate and late-stage HCC (P<0.01 for both assays). Receiver operating characteristic (ROC) curve analysis showed that with a specificity of >95%, the area under the ROC curve (AUC) was 0.62 with 11.4% sensitivity for anti-p16a assay, 0.68 with 14.3% sensitivity for anti-CD25a IgG assay and 0.64 with 10.1% sensitivity for anti-FOXP3 assay. Of the three groups of HCC patients, group 3 (BCLC stage C+D) showed the best sensitivity for the detection of plasma anti-p16a and anti-FOXP3 IgG levels with an AUC of 0.66 and 0.65.

Conclusion

Circulating IgG antibody to p16a, CD25a and FOXP3 proteins may be a useful biomarker for assessment of HCC prognosis of this malignancy, especially in male patients with HCC.

Circulating natural antibodies to inflammatory cytokines are potential biomarkers for atherosclerosis

Background

Inflammatory cytokines contribute to the development of atherosclerosis. Natural antibodies in the circulation have protective effects on common diseases including atherosclerosis-related conditions.

Purpose

The present study aimed to investigate the possible involvement of circulating IgG antibodies against inflammatory cytokines in atherosclerosis.

Methods

A total of 220 patients with diagnosis of atherosclerosis and 200 healthy controls were recruited. Seven linear peptide antigens were used to develop an enzyme-linked immunosorbent assay in-house for detection of plasma IgG antibodies against interleukin 1β (fragments IL1β-1 and IL1β-2), IL6, IL8, tumor necrosis factor alpha (fragments TNFα-1 and TNFα-2) and IL1α.

Results

Atherosclerotic patients had an increase in the levels of circulating IgG to TNFα-1(adjusted r² = 0.038, p < 0.001) and IL1α (adjusted r² = 0.025, p = 0.002) compared with control subjects. Female patients mainly contributed to increased anti-TNFα-1 IgG levels (adjusted r² = 0.073, p < 0.001) and anti-IL1α IgG levels (adjusted r² = 0.044, p = 0.003). In addition, female patients showed higher anti-IL1β-2 IgG levels than controls (adjusted r² = 0.023, p = 0.026). There was no significant change of circulating IgG antibodies to other cytokines. ROC curve analysis showed an AUC of 0.564 for anti-TNFα-1 IgG assay with 22.8% sensitivity against a specificity of 90.0%, and an AUC of 0.539 for anti-IL1α IgG assay with 17.8% sensitivity against a specificity of 90.0%; the anti-IL1β-2 IgG assay had an AUC of 0.580 with 26.3% sensitivity against a specificity of 89.8% in female patients. There was no correlation between plasma IgG levels and carotid intima-media thickness.

Conclusion

Natural antibodies to inflammatory cytokines may be potential biomarkers for atherosclerosis.

Association of antibody to E2 protein of human papillomavirus and p16INK4A with progression of HPV-infected cervical lesions

Human papillomavirus (HPV) E2 and L1 proteins are expressed in cervical cells during the lytic stage of infection. Overexpression of p16^INK4A is a biomarker of HPV-associated cervical neoplasia. This study investigated antibodies to HPV16 E2, HPV16 L1, and p16^INK4A in sera from women with no squamous intraepithelial lesion (No-SIL) of the cervix, low-grade SIL, high-grade SIL, and cervical squamous cell carcinoma (SCC). HPV DNA was detected by polymerase chain reaction. Anti-E2, -L1, and -p16^INK4A antibodies in sera were determined by western blot. Among 116 samples, 69 (60%) were HPV DNA-positive. Percentages seropositive for anti-E2, -L1, and -p16^INK4A antibodies were 39.6, 22.4, and 23.3%, respectively. Anti-E2 antibody was significantly correlated with HPV DNA-positive cases. Eighty-seven women (75%) were regarded as infected with HPV, having at least one positive result from HPV DNA, L1, or E2 antibody. Antibody to p16^INK4A was associated with HPV infection (odds = 5.444, 95% CI 1.203-24.629, P = 0.028) and precancerous cervical lesions (odds = 5.132, 95% CI 1.604-16.415, P = 0.006). Interestingly, the concurrent detection of anti-E2 and -p16^INK4A antibodies was significantly associated with HPV infection (odds = 1.382, 95% CI 1.228-1.555, P = 0.044). These antibodies might be good candidate biomarkers for monitoring HPV-associated cervical lesion development to cancer.

Further study of circulating IgG antibodies to CD25-derived peptide antigens in nonsmall cell lung cancer

A recent study reported that circulating antibodies to CD25-derived peptide antigens were significantly higher in patients with nonsmall cell lung cancer (NSCLC) than control subjects. The present study was, thus, undertaken to replicate the initial finding with different sample sets. An in-house ELISA was applied to determine circulating IgG antibodies to linear peptide antigens derived from CD25. A total of 111 patients with NSCLC and 216 control subjects were recruited and divided into the discovery sample (51 vs 108) and the validation sample (60 vs 108) based on the time of sampling. Student's t test showed that circulating anti-CD25 IgG levels were significantly higher in the patient group than the control group (t = 2.23, P = 0.027) and the validation sample replicated this finding (t = 3.31, P = 0.0012), generating a combined P value of 0.0004 (χ(2) = 20.8, df = 4). Fisher's combining probability revealed that patients with stage IV NSCLC had a significant increase in anti-CD25 IgG levels compared with control subjects (χ(2) = 22.1, df = 4, P = 0.0002) but those with the other three stages did not. This study suggests that circulating anti-CD25 IgG antibodies may have prognostic rather than early diagnostic values for lung cancer.