Anti‐p53 autoantibody in blood as a diagnostic biomarker for colorectal cancer: A meta‐analysis

Screening colorectal cancer associated autoantigens through multi-omics analysis and diagnostic performance evaluation of corresponding autoantibodies

BACKGROUND

This study aims to screen, validate novel biomarkers and develop a user-friendly online tool for the detection of colorectal cancer (CRC).

METHODS

Multi-omics approach, comprising proteomic analysis and single-cell transcriptomic analysis, was utilized to discover candidate tumor-associated antigens (TAAs). The presence of tumor-associated autoantibodies (TAAbs) in serum was subsequently assessed using enzyme-linked immunosorbent assays (ELISA) in 300 CRC patients and 300 healthy controls. Ten machine learning algorithms were utilized to develop diagnostic models, with the optimal one selected and integrated into an R Shiny-based GUI to enhance usability and accessibility.

RESULTS

We identified twelve potential TAAs: HMGA1, NPM1, EIF1AX, CKS1B, HSP90AB1, ACTG1, S100A11, maspin, ANXA3, eEF2, P4HB, and HKDC1. ELISA results showed that five TAAbs including anti-CKS1B, anti-S100A11, anti-maspin, anti-ANXA3, and anti-eEF2 were potential diagnostic biomarkers during the diagnostic evaluation phase (all P < 0.05). The Random Forest model yielded an AUC of 0.82 (95% CI: 0.78-0.88) on the training set and 0.75 (95% CI: 0.68-0.82) on the test set, demonstrating the robustness of the results. Web-based implementations of CRC diagnostic tools are publicly accessible via weblink https://qzan.shinyapps.io/CRCPred/ .

CONCLUSIONS

A five biomarker panel can server as complementary biomarker to CEA and CA19-9 in CRC detection.

Anti-FDX1 Autoantibody as a Potential Biomarker for Non-Small Cell Lung Cancer Detection

BACKGROUND

Autoantibodies can be readily identified prior to biopsy and may serve as valuable biomarkers for cancer detection. Ferredoxin 1 (FDX1) is a key regulator in the process of cuproptosis and affects the prognosis of lung cancer. In this study, we investigated whether the anti-FDX1 autoantibody could serve as a novel biomarker for the detection of non-small cell lung cancer (NSCLC).

METHODS

A total of 1,155 plasma samples were divided into the verification and validation groups. The expression levels of the anti-FDX1 autoantibody in 414 patients with NSCLC, 327 patients with benign pulmonary nodules (BPN), and 414 normal controls (NC) were detected using ELISA. Western blotting and immunofluorescence analyses were performed to confirm the ELISA results.

RESULTS

Plasma anti-FDX1 autoantibody levels were significantly higher in patients with NSCLC than in patients with BPN and NCs in the verification and validation groups. The ELISA results were confirmed by Western blotting and immunofluorescence. The anti-FDX1 autoantibody distinguished NSCLC from NC and BPN with an AUC (95% confidence interval) of 0.806 (0.772-0.839) and 0.627 (0.584-0.670), respectively.

CONCLUSIONS

Our study demonstrated the potential benefits of the anti-FDX1 autoantibody as a novel biomarker for NSCLC detection.

IMPACT

These findings suggested that the anti-FDX1 autoantibody may facilitate the detection of NSCLC.

Blood-based biomarkers and novel technologies for the diagnosis of colorectal cancer and adenomas: a narrative review

Aim: Blood-based biomarkers have shown promise for diagnosing colorectal cancer (CRC) and adenomas (CRA). This review summarizes recent studies in this area. Methods: A literature search was undertaken for 01/01/2017-01/03/2023. Criteria included CRC, CRA, liquid-biopsy, blood-based tests and diagnosis. Results: 12,378 studies were reduced to 178 for data extraction. Sixty focused on proteomics, 53 on RNA species, 30 on cfDNA methylation, seven on antigens and autoantibodies and 28 on novel techniques. 169 case control and nine cohort studies. Number of participants ranged 100-54,297, mean age 58.26. CRC sensitivity and specificity ranged 9.10-100% and 20.40-100%, respectively. CRA sensitivity and specificity ranged 8.00-95.70% and 4.00-97.00%, respectively. Conclusion: Sensitive and specific blood-based tests exist for CRC and CRA. However, studies demonstrate heterogenous techniques and reporting quality. Further work should concentrate on validation and meta-analyzes.

Prediction of high visceral adipose tissue for sex-specific community residents in Taiwan

Visceral adipose tissue accumulation is strongly linked with numerous chronic diseases; however, the accessibility for visceral adipose tissue measurement is limited. This study employed a cross-sectional design to determine the optimal strongest predictor of high visceral adipose tissue in each sex and identified the optimal cutoff value thereof. Purposive sampling was used to recruit 94 men and 326 women aged ≥40 years in southern Taiwan. Receiver operating characteristic curve analysis was used to explore the optimal predictor of high visceral adipose tissue (defined as ≥135 cm2 for men and ≥100 cm2 for women) in each sex. The waist-to-hip ratio was the strongest predictor for men, with a cutoff value of 0.96 yielding the maximum sensitivity (94.29%) and specificity (93.22%). By contrast, body mass index was the strongest predictor for women, with a cutoff value of 25.45 kg/m2 yielding the maximum sensitivity (87.18%) and specificity (87.55%). The results may serve as a reference for health policy-makers in screening for high visceral adipose tissue to identify individuals at high risk of developing chronic diseases for health promotion.

Autoantibody repertoire profiling in tissue and blood identifies colorectal cancer-specific biomarkers

Autoantibodies (AAbs) in the blood of colorectal cancer (CRC) patients have been evaluated for tumor detection. However, it remains uncertain whether these AAbs are specific to tumor-associated antigens. In this study, we explored the IgG and IgM autoantibody repertoires in both the in situ tissue microenvironment and peripheral blood as potential tumor-specific biomarkers. We applied high-density protein arrays to profile AAbs in the tumor-infiltrating lymphocyte supernatants and corresponding serum from four patients with CRC, as well as in the serum of three noncancer controls. Our findings revealed that there were more reactive IgM AAbs than IgG in both the cell supernatant and corresponding serum, with a difference of approximately 3-5 times. Immunoglobulin G was predominant in the serum, while IgM was more abundant in the cell supernatant. We identified a range of AAbs present in both the supernatant and the corresponding serum, numbering between 432 and 780, with an average of 53.3% shared. Only 4.7% (n = 23) and 0.2% (n = 2) of reactive antigens for IgG and IgM AAbs, respectively, were specific to CRC. Ultimately, we compiled a list of 19 IgG AAb targets as potential tumor-specific AAb candidates. Autoantibodies against one of the top candidates, p15INK4b-related sequence/regulation of nuclear pre-mRNA domain-containing protein 1A (RPRD1A), were significantly elevated in 53 CRC patients compared to 119 controls (p < 0.0001). The project revealed that tissue-derived IgG AAbs, rather than IgM, are the primary source of tumor-specific AAbs in peripheral blood. It also identified potential tumor-specific AAbs that could be applied for noninvasive screening of CRC.

Cancer Relevance of Circulating Antibodies Against LINE-1 Antigens in Humans

Long interspersed nuclear element-1 (LINE-1 or L1), the most abundant family of autonomous retrotransposons occupying over 17% of human DNA, is epigenetically silenced in normal tissues by the mechanisms involving p53 but is frequently derepressed in cancer, suggesting that L1-encoded proteins may act as tumor-associated antigens recognized by the immune system. In this study, we established an immunoassay to detect circulating autoantibodies against L1 proteins in human blood. Using this assay in >2,800 individuals with or without cancer, we observed significantly higher IgG titers against L1-encoded ORF1p and ORF2p in patients with lung, pancreatic, ovarian, esophageal, and liver cancers than in healthy individuals. Remarkably, elevated levels of anti-ORF1p-reactive IgG were observed in patients with cancer with disease stages 1 and 2, indicating that the immune response to L1 antigens can occur in the early phases of carcinogenesis. We concluded that the antibody response against L1 antigens could contribute to the diagnosis and determination of immunoreactivity of tumors among cancer types that frequently escape early detection.

SIGNIFICANCE

The discovery of autoantibodies against antigens encoded by L1 retrotransposons in patients with five poorly curable cancer types has potential implications for the detection of an ongoing carcinogenic process and tumor immunoreactivity.

p53 and p63 Proteoforms Derived from Alternative Splicing Possess Differential Seroreactivity in Colorectal Cancer with Distinct Diagnostic Ability from the Canonical Proteins

Colorectal cancer (CRC) is the third most common cancer and the second most frequent cause of cancer-related death worldwide. The detection in plasma samples of autoantibodies against specific tumor-associated antigens has been demonstrated to be useful for the early diagnosis of CRC by liquid biopsy. However, new studies related to the humoral immune response in cancer are needed to enable blood-based diagnosis of the disease. Here, our aim was to characterize the humoral immune response associated with the different p53 and p63 proteoforms derived from alternative splicing and previously described as aberrantly expressed in CRC. Thus, here we investigated the diagnostic ability of the twelve p53 proteoforms and the eight p63 proteoforms described to date, and their specific N-terminal and C-terminal end peptides, by means of luminescence HaloTag beads immunoassays. Full-length proteoforms or specific peptides were cloned as HaloTag fusion proteins and their seroreactivity analyzed using plasma from CRC patients at stages I-IV (n = 31), individuals with premalignant lesions (n = 31), and healthy individuals (n = 48). p53γ, Δ40p53β, Δ40p53γ, Δ133p53γ, Δ160p53γ, TAp63α, TAp63δ, ΔNp63α, and ΔNp63δ, together with the specific C-terminal end α and δ p63 peptides, were found to be more seroreactive against plasma from CRC patients and/or individuals with premalignant lesions than from healthy individuals. In addition, ROC (receiver operating characteristic) curves revealed a high diagnostic ability of those p53 and p63 proteoforms to detect CRC and premalignant individuals (AUC higher than 85%). Finally, electrochemical biosensing platforms were employed in POC-like devices to investigate their usefulness for CRC detection using selected p53 and p63 proteoforms. Our results demonstrate not only the potential of these biosensors for the simultaneous analysis of proteoforms' seroreactivity, but also their convenience and versatility for the clinical detection of CRC by liquid biopsy. In conclusion, we here show that p53 and p63 proteoforms possess differential seroreactivity in CRC patients in comparison to controls, distinctive from canonical proteins, which should improve the diagnostic panels for obtaining a blood-based biomarker signature for CRC detection.

Cancer Is Associated with the Emergence of Placenta-Reactive Autoantibodies

Placenta-specific antigens are minimally expressed or unexpressed in normal adult tissues, while they are widely expressed in cancer. In the course of carcinogenesis, a vast array of autoantibodies (AAbs) is produced. Here, we used a quantitative approach to determine the reactivity of AAbs in the sera of patients with breast (BrC: N = 100, 100% female, median age: 51 years), gastric (GC: N = 30, 46.6% female, median age: 57 years), bladder (BC: N = 29, 34.4% female, median age: 57 years), and colorectal (CRC: N = 34, 41.1% female, median age: 51 years) cancers against first-trimester (FTP) and full-term placental proteome (TP) in comparison with age- and sex-matched non-cancer individuals. Human-on-human immunohistochemistry was used to determine reactive target cells in FTP. The effect of pregnancy on the emergence of placenta-reactive autoantibodies was tested using sera from pregnant women at different trimesters of pregnancy. Except for BC, patients with BrC (p < 0.0284), GC (p < 0.0002), and CRC (p < 0.0007) had significantly higher levels of placenta-reactive AAbs. BrC (p < 0.0001) and BC (p < 0.0409) in the early stages triggered higher autoantibody reactivity against FTP. The reactivities of BrC sera with FTP did not show an association with ER, PR, or HER2 expression. Pregnancy in the third trimester was associated with the induction of TP- and not FTP-reactive autoantibodies (=0.018). The reactivity of BrC sera with placental proteins was found to be independent of gravidity or abortion. BrC sera showed a very strong and specific pattern of reactivity with scattered cells beneath the syncytiotrophoblast layer. Our results reinforce the concept of the coevolution of placentation and cancer and shed light on the future clinical application of the placental proteome for the non-invasive early detection and treatment of cancer.

Constructing a prognostic immune-related lncRNA model for colon cancer

Colon cancer is a common digestive tract tumor. Although many gene prognostic indicators have been used to predict the prognosis of colon cancer patients, the accuracy of these prognostic indicators is still uncertain. Thus, it is necessary to construct a model for the prognostic analysis of colon cancer. We downloaded the original transcriptome data of colon cancer and performed a differential coexpression analysis of immune-related genes to obtain different immune-related long noncoding RNAs, which were paired as differentially expressed immune-related lncRNA pairs (DEirlncRNAPs). Then, the 1-year overall survival rate receiver operating characteristic curve was calculated, and the Akaike information criterion value was evaluated to determine the maximum inflection point, which was used as the cutoff point to identify groups of colon cancer patients at high and low risk for death. Subsequently, the optimal prediction model was established. Finally, we used the patients' survival times, clinicopathological features, tumor infiltrating immune cells, chemotherapy responses, and immunosuppressive biomarkers to verify the DEirlncRNAP model. Seventy-one DEirlncRNAPs were obtained to build the risk assessment model. The patients were divided into a high-risk group and a low-risk group according to the cutoff point. Then, the DEirlncRNAP model was verified using patient survival times, clinicopathological features, tumor-infiltrating immune cells, chemotherapy responses, and immunosuppressive biomarkers. A new DEirlncRNAP model for predicting the prognosis of colon cancer patients was established, which could reveal new insights into the relationships of colon cancer with tumor-infiltrating immune cells and antitumor immunotherapy.

Performance of screening tests for esophageal squamous cell carcinoma: a systematic review and meta-analysis

BACKGROUND AND AIMS

This systematic review and meta-analysis aims to compare the pooled diagnostic accuracy of the currently available esophageal squamous cell carcinoma (ESCC) screening tests.

METHODS

A comprehensive literature search of Embase and Medline (up to October 31, 2020) was performed to identify eligible studies. We pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio for ESCC screening tools using a bivariate random-effects model. The summary receiver operating characteristic curves with area under the curve (AUC) were plotted for each screening test.

RESULTS

We included 161 studies conducted in 81 research articles involving 32,209 subjects. The pooled sensitivity, specificity, and AUC of the major screening tools were respectively as follows: endoscopy (peroral endoscopy): .94 (95% confidence interval [CI], .87-.97), .92 (95% CI, .87-.95), and .97 (95% CI, .96-.99); endoscopy (transnasal endoscopy): .85 (95% CI, .70-.93), .96 (95% CI, .91-.98), and .97 (95% CI, .95-.98); microRNA: .77 (95% CI, .75-.80), .78 (95% CI, .75-.80), and .85 (95% CI, .81-.87); autoantibody: .45 (95% CI, .36-.53), .91 (95% CI, .89-.93), and .84 (95% CI, .81-.87); and cytology: .82 (95% CI, .60-.93), .97 (95% CI, .88-.99), and .97 (95% CI, .95-.98). There was high heterogeneity.

CONCLUSIONS

The diagnostic accuracy seemed to be comparable between cytology and endoscopy, whereas autoantibody and microRNAs bear potential as future noninvasive screening tools for ESCC. To reduce ESCC-related death in high-risk populations, it is important to develop a more accurate and less-invasive screening test.

Isotypic analysis of anti-p53 serum autoantibodies and p53 protein tissue phenotypes in colorectal cancer

The presence of IgA- and IgM-specific autoantibody (AAb) isotypes and their relationship to p53 tissue expression patterns are not well understood. This study aims to investigate the clinical utility of the anti-p53 AAb isotypes and tissue positivity in colorectal cancer (CRC). We analysed anti-p53 IgG, IgM, and IgA AAbs in sera of 99 CRC patients and 99 non-cancer control subjects. Corresponding tissue expression of the p53 protein was evaluated by immunohistochemistry (IHC). Anti-p53 AAbs of the IgG isotype were present in the sera of 21 out of 99 patients (21%), while IgM AAbs were observed in 9 (9%) and IgA in 2 (2%) CRC patients. Anti-p53 AAbs of all three isotypes were generally associated with IHC staining indicative of mutated TP53. Seropositive anti-p53 IgM cases in the absence of anti-p53 IgG were linked to wild-type p53. Anti-p53 IgA in the absence of IgG AAbs was detected in two non-cancer controls indicating a potential p53 epitope mimicry. Although seropositivity was not associated with patient survival (P = 0.650), mutant-pattern p53 tissue expression was associated with reduced 5-year overall survival (P = 0.032), however, it was not an independent prognostic marker (Multivariate Cox regression, P = 0.193). In conclusion, immunoglobulin isotyping revealed that anti-p53 IgM and IgA AAbs were predominantly concurrent with anti-p53 serum IgG and the mutant-pattern p53 tissue phenotype. IgM and IgA seropositive cases in absence of anti-p53 IgG were linked to wild-type p53 tissue phenotype indicating early anti-p53 immune responses preceding isotype class-switch (IgM) or p53 antigen mimicry (IgA).

Highly sensitive wide-range target fluorescence biosensors of high-emittance metasurfaces

We demonstrate highly sensitive fluorescence (FL) biosensors made of plasmon-photon-hybrid high-emittance metasurfaces, which are hybrid structures composed of perforated silicon waveguides and stacked complementary (SC) gold nanostructures. The SC metasurfaces are applicable to a wide range of targets from antibodies to nucleic acids. As a test bed, a representative antibody of immunoglobulin G is immobilized on the metasurfaces through microfluidic paths and then is directly detected in a scaled manner even at a very low concentration of 5 pg mL^-1, i.e., 34 fM. Moreover, a cancer marker of p53 antibody is indirectly detected on the SC metasurfaces at a low concentration of 50 pg mL^-1, which is significantly lower than the medical diagnosis criterion of a few ng mL^-1. Furthermore, single-strand DNAs that are oligonucleotides and complementary to SARS-CoV-2 RNA are detected with 1 h immobilization time in the range of fmol mL^-1 in a scaled manner. These experimental results indicate that the present FL metasurface sensors function efficiently as biosensors for a wide range of biomarkers.

Usefulness of Serum Anti-p53 Antibody Measurement in Patients Undergoing Hepatectomy for Colorectal Liver Metastases

BACKGROUND

While anti-p53 antibody (p53-Ab) is a potential marker for early detection of colorectal cancer, its clinical utility in patients with advanced colorectal cancer remains unknown.

METHODS

The clinical significance of p53-Ab was investigated by analyzing the data of 206 patients who underwent curative resection for colorectal liver metastases.

RESULTS

Of the 206 patients, 60 (29%) were seropositive and 146 were seronegative for p53-Ab before the surgery. The preoperative serum p53-Ab level showed no significant correlation with the serum CEA or serum CA19-9 levels. The perioperative changes in serum p53-Ab positivity were significantly correlated with the preoperative serum p53-Ab levels and multivariate analysis confirmed that a higher preoperative p53-Ab level was independently associated with a worse recurrence-free survival (hazard ratio [HR], 1.07; 95% CI, 1.01-1.13; P = 0.033 per + 100 U/mL), even after adjustments for other oncological factors, including the preoperative serum CEA level.

CONCLUSION

Higher preoperative p53-Ab levels were associated with a higher risk of recurrence after curative resection of colorectal liver metastases.

Autoantibody Formation and Mapping of Immunogenic Epitopes against Cold-Shock-Protein YB-1 in Cancer Patients and Healthy Controls

Simple Summary

Cold shock Y-box binding protein-1 plays a crucial role in cancerous cell transformation and proliferation. Experimental evidence links autoantibody formation with cancer diseases as well as YB 1 protein levels. Hence, we investigated autoantibody formation targeting YB-1 in cancer patients. Using recombinant proteins and specific peptide arrays, we mapped linear epitopes, which localize in the cold shock and C-terminal domain of the protein, in cancer patients that differ from healthy controls. Furthermore, cancer sera containing autoantibodies that target YB-1 extend the half-life of the YB-1 protein. Since extracellular YB-1 serves as a ligand for receptor Notch3 as well as TNFR1, this may contribute to aberrant signaling that promotes tumor development. In the clinical setting, we envision setting up detection assays for the immune response against YB-1, which may aid in screening for cancer.

Abstract

Cold shock Y-box binding protein-1 participates in cancer cell transformation and mediates invasive cell growth. It is unknown whether an autoimmune response against cancerous human YB-1 with posttranslational protein modifications or processing develops. We performed a systematic analysis for autoantibody formation directed against conformational and linear epitopes within the protein. Full-length and truncated recombinant proteins from prokaryotic and eukaryotic cells were generated. Characterization revealed a pattern of spontaneous protein cleavage, predominantly with the prokaryotic protein. Autoantibodies against prokaryotic, but not eukaryotic full-length and cleaved human YB-1 protein fragments were detected in both, healthy volunteers and cancer patients. A mapping of immunogenic epitopes performed with truncated E. coli-derived GST-hYB-1 proteins yielded distinct residues in the protein N- and C-terminus. A peptide array with consecutive overlapping 15mers revealed six distinct antigenic regions in cancer patients, however to a lesser extent in healthy controls. Finally, a protein cleavage assay was set up with recombinant pro- and eukaryotic-derived tagged hYB-1 proteins. A distinct cleavage pattern developed, that is retarded by sera from cancer patients. Taken together, a specific autoimmune response against hYB-1 protein develops in cancer patients with autoantibodies targeting linear epitopes.

Uselessness of Serum p53 Antibody for Detecting Colitis-associated Cancer in the Era of Immunosuppressive Therapy

BACKGROUND/AIM

The present study examined the utility of serum p53 antibody (Ab) for detecting colitis-associated cancer (CAC) in the era of immunosuppressive therapy.

PATIENTS AND METHODS

Two hundred and fifty patients were analyzed, 219 had no carcinoma or dysplasia (Group non-CAC), and 31 had carcinoma or dysplasia (Group CAC). Serum p53 Abs were detected with an enzyme-linked immunosorbent assay. Immunohistochemical detection was performed in Group CAC.

RESULTS

Immunosuppressive therapy was performed in 98.1% of Group non-CAC and 80.6% of Group CAC. There were no differences in serum p53 Abs positivity between Groups non-CAC and CAC (8.7% vs. 3.2%, p=0.30). p53 staining positivity was noted in 90.3% of Group CAC, and the rate of serum p53 positivity was significantly lower in patients with immunosuppressive therapy than in those without in Group CAC (0.0% vs. 16.7%, p=0.04).

CONCLUSION

The utility of serum p53 Ab for detecting CAC is dubious in the era of immunosuppressive therapy.

New Assay System Elecsys Anti-p53 to Detect Serum Anti-p53 Antibodies in Esophageal Cancer Patients and Colorectal Cancer Patients: Multi-institutional Study

BACKGROUND

Several recent studies suggest that serum anti-p53 antibodies (s-p53-Abs) may be combined with other markers to detect esophageal and colorectal cancer. In this study, we assessed the sensitivity and specificity of s-p53-Abs detection of a new electrochemiluminescence immunoassay (ECLIA; Elecsys anti-p53).

METHODS

Elecsys anti-p53 assay was used to analyze the level of s-p53-Abs in blood sera from patients with esophageal or colorectal cancer taken before treatment. Control blood sera from healthy volunteers, patients with benign diseases, and patients with autoimmune diseases served as a reference. In addition, squamous cell carcinoma antigen (SCC-Ag) and cytokeratin 19 fragments (CYFRA21-1) were assessed in patients with esophageal cancer, and carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 were assessed in patients with colorectal cancer.

RESULTS

Samples from 281 patients with esophageal cancer, 232 patients with colorectal cancer, and 532 controls were included in the study. The median value of s-p53-Abs in control samples was < 0.02 μg/mL (range < 0.02-29.2 μg/mL). Assuming 98% specificity, the cut-off value was determined as 0.05 μg/mL. s-p53-Abs were detected in 20% (57/281) of patients with esophageal cancer and 18% (42/232) of patients with colorectal cancer. In combination with SCC-Ag and CEA, respectively, s-p53-Abs detected 51% (144/281) of patients with esophageal and 53% (124/232) of patients with colorectal cancer.

CONCLUSIONS

The new s-p53-Abs assay Elecsys anti-p53 was useful in detecting esophageal and colorectal cancers with high specificity. Adding s-p53-Abs to conventional markers significantly improved the overall detection rates.

Auto-antibodies against apolipoprotein A-1 block cancer cells proliferation and induce apoptosis

Auto-antibodies against apoA-1 (anti-apoA-1 IgGs) have been identified as important actors of atherosclerosis development through pro-inflammatory and pro-atherogenic properties and to also induce apoptosis in tumoral neuronal and lymphocyte derived cell lines through unknown mechanisms. The purpose of this study was to explore the cellular pathways involved in tumoral cell survival modulated by anti-apoA-1 antibodies. We observed that anti-apoA-1 antibodies induce growth arrest (in G2/M phase) and cell apoptosis through caspase 3 activation, accompanied by a selective p53 phosphorylation on serine 15. RNA sequencing indicated that anti-apoA-1 IgGs affect the expression of more than 950 genes belonging to five major groups of genes and respectively involved in i) cell proliferation inhibition, ii) p53 stabilisation and regulation, iii) apoptosis regulation, iv) inflammation regulation, and v) oxidative stress. In conclusion, anti-apoA-1 antibodies seem to have a role in blocking tumoral cell proliferation and survival, by activating a major tumor suppressor protein and by modulating the inflammatory and oxidative stress response. Further investigations are needed to explore a possible anti-cancer therapeutic approach of these antibodies in very specific and circumscribed conditions.

Serum Analysis of Women with Early-Stage Breast Cancer Using a Mini-Array of Tumor-Associated Antigens

Background: Several studies have shown that patients with cancer have antibodies in serum that react with cellular autoantigens, known as Tumor-Associated Antigens (TAA). The present work aimed to determine whether a mini-array comprising four recombinant TAA increases the detection of specific serum antibodies for the diagnosis of early-stage breast cancer. Methods: The mini-array included Alpha 1-AntiTrypsin (A1AT), TriosePhosphate Isomerase 1 (TPI1), Peptidyl-Prolyl cis-trans Isomerase A (PPIA), and PeroxiReDoXin 2 (PRDX2) full-length recombinant proteins. The proteins were produced after gene cloning, expression, and purification, and were verified by Western blot assays. Then, Dot-Blot was performed to find antibodies against the four TAA in 12 sera from women with early-stage breast cancer (stage II) and 12 sera from healthy women. Results: Antibody detection against individual TAA in early-stage breast cancer sera ranged from 58.3% to 83.3%. However, evaluation of the four TAA showed that there was a positive antibody reaction reaching a sensitivity of 100% and a specificity of 85% in early-stage breast cancer, suggesting that this mini-array must be evaluated as a clinical diagnostic tool for early-stage breast cancer in a larger sample size. Conclusion: Our results suggest that TAA mini-arrays may provide a promising and powerful method for improving the detection of breast cancer in Mexican women.

Autoantibodies to tumor-associated antigens in lung cancer diagnosis

Lung cancer (LC) accounts for the majority of cancer-related deaths worldwide. Although screening the high-risk population by low-dose CT (LDCT) has reduced mortality, the cost and high false positivity rate has prevented its general diagnostic use. As such, better and more specific minimally invasive biomarkers are needed in general and for early LC detection, specifically. Autoantibodies produced by humoral immune response to tumor-associated antigens (TAA) are emerging as a promising noninvasive biomarker for LC. Given the low sensitivity of any one single autoantibody, a panel approach could provide a more robust and promising strategy to detect early stage LC. In this review, we summarize the background of TAA autoantibodies (TAAb) and the techniques currently used for identifying TAA, as well as recent findings of LC specific antigens and TAAb. This review provides guidance toward the development of accurate and reliable TAAb as immunodiagnostic biomarkers in the early detection of LC.