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Background One of the most frequently diagnosed oncological diseases among young persons is Low-grade glioma (LGG). More than 80% of LGGs progress to higher-grade tumors always lethal to a patient. LGG is an extremely heterogeneous group of primary glial brain tumors with a quite variable rate of recurrence, survival, and response to treatment. Thus a study of new biomarkers associated with disease progression and patient outcome is useful to improve patient management. Genes involved in key cellular processes, e.g., apoptosis, are promising prognostic and predictive cancer markers. Phosphatidylserine (PS) plays an essential role in apoptosis signaling. Several studies suggested PS is dysregulated in the tumor microenvironment and offends the development of anti-cancer immune response. The scramblases PLSCR1 and XKR8 allegedly could be associated with the progression and outcome of LGG since they could be involved in the development of immunity via regulation of PS activity by its bidirectional translocation in the plasma membrane. Thus this study was aimed to evaluate associations of PLSCR1 and XKR8 with disease-free and overall survival of LGG patients. Methods Gene expression values and clinical information of 530 LGG patients were downloaded from TCGA Low-Grade Glioma study using the public resource CBioPortal. According to gene expression values (RNA Seq V2 RSEM) patients were divided into two groups: with downregulated ( mean) PLSCR1 or XKR8 gene. The Kaplan-Meier procedure and Log-Rank test were used for survival analysis. All calculations were performed in the integrated development environment - RStudio. Results It was shown the LGG patients with upregulated PLSCR1 (p = 2.54e-14) and XKR8 (p = 7.33e-15) gene had worse disease prognosis than other patients. Similar associations were seen in the study of LGG progression, where patients with upregulated PLSCR1 (p = 7.75e-07) and XKR8 (p = 5.59e-10) gene had a higher risk of cancer recurrence. Conclusions Consequently, PLSCR and XKR8 genes could be considered as new prognostic biomarkers of LGG progression and outcome. Legal entity responsible for the study Research Laboratory "Biomarker". Funding The work was performed according to the Russian Government Program of Competitive Growth of KFU. Disclosure All authors have declared no conflicts of interest.

Triple-negative (TN) breast cancer (BC) is the most aggressive molecular subtype of BC that affected over 250 thousand females worldwide just in 2018. Patients with TNBC have exhibited a higher probability of cancer relapses and poor prognosis of disease outcome which are due to the absence of established and reliable targets for therapy of this subtype of tumors. Only 10% of TN breast tumors have BRCA1/2 mutations associated with high sensitivity of cancer cells to the chemotherapy with platinum salts drugs (e.g., cisplatin, carboplatin (Cb), etc.) and PARP-inhibitors. Recent studies indicated that administration of Cb in neoadjuvant chemotherapy of TNBC increase pCR (pathologic complete response) of patients received Cb in comparison with a control group. Also, Phase II and III of clinical trials have shown that TNBC patients respond differently to adjuvant chemotherapy with Cb. Therefore further studies are required to define subgroups of TNBC patients, which might benefit from carboplatin therapy. In our previous studies, the RAD50 gene involved in radiation-induced DNA double-strand break repair was identified as a tumor-associated antigen and potential BC marker. We have shown that low expression of RAD50 gene is associated with better TNBC prognosis. The current study was aimed to evaluate RAD50 as a predictive marker of TNBC cells sensitivity to Cb. The RAD50 gene was silenced in triple negative breast cancer cell lines with wild-type BRCA genes namely MDA-MB-231, MDA-MB-436, and MDA-MB-453 by RNA interference. Then the changes of the cytotoxic sensitivity of these cells to Cb treatment in comparison to the control cells with original RAD50 expression were investigated by using a cell viability assay. Obtained data were analyzed by the Wilcoxon signed-rank test. The statistical analysis was performed using GraphPad Prism 7 software. Results of this study demonstrated that the knockdown of RAD50 gene expression in human TNBC cells could significantly increase their susceptibility to treatment with Cb (MDA-MB-231: IC50 - 20,65uM (silenced RAD50) and 24,93uM (control), p-value = 0,0098; MDA-MB-436: IC50 - 7,497uM (silenced RAD50) and 10,39uM (control), p-value = 0,0137; MDA-MB-453: IC50 - 7,336uM (silenced RAD50) and 8,711uM (control), p-value = 0,002). These results strongly indicate that silencing of the RAD50 expression contributes to the sensitization of TNBC cells to treatment with platinum-based drug Cb. Therefore RAD50 could be considered as important TNBC predictive biomarker. Further validation of RAD50 by using the tumors of TNBC patients and animal xenograft models could prove to be essential to use this marker for improving the therapy regimens of TNBC tumors without BRCA1/2 mutations. This work is performed according to the Russian Government Program of Competitive Growth of Kazan Federal University. Citation Format: Kristina V. Havrysh, Mikhail V. Bogdanov, Ramziya G. Kiyamova. Silencing of the RAD50 gene contributes to enhancing the sensitivity of the triple-negative breast cancer cells to carboplatin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4927.

Purpose. To investigate a frequency of antibody response to SEREX-identified medullary breast carcinoma autoantigens ZRF1 and KRR1 in sera of breast cancer patients taking into account clinical and molecular characteristics of tumors for opening of new perspectives in creation of minimally invasive immunological tests for cancer diagnostics.Methods. Enzyme-linked immunosorbent assay and bioinformatics analysis.Results. Increased frequency of antibody response was found in sera of breast cancer patients to ZRF and KRR1 antigens. The antibody response to these antigens was higher in sera of patients with invasive ductal carcinoma than in sera of patients with other histological types of breast tumors. Moreover, more frequent antibody response to ZRF antigen was found in sera of patients with less aggressive tumors. The sequence analysis of ZRF1 antigen SEREX clones obtained from cDNA libraries of different tumors demonstrates that they encode different protein isoforms.Conclusion. Tumor-associated antigens KRR1 and ZRF1 and their cognate autoantibodies could be considered as potential molecular markers of breast cancer which need to be further investigated.

Background: Autoantibodies, which are produced against tumor-associated antigens, are potential tumor markers and attract a growing interest for cancer detection, differential diagnostics and prognosis.Objective: To evaluate the diagnostic significance of 40 antigens identified by immunoscreening of cDNA libraries from thyroid and colon cancers by allogenic screening with different tumor types patients’ sera.Method: Plaque-spot serological assay.Results: Increased frequency of antibody response in sera of cancer patients compared with that of healthy donors was shown toward 14 antigens, 8 of which (CG016, BTN3A3, FKBP4, XRCC4, TSGA2, ACTR1A, FXYD3 and CTSH) have revealed exclusively cancer-related serological profile.Conclusion: Allogenic screening of 40 SEREX-antigens with sera from cancer patients and healthy donors allowed us to reveal 14 antigens with potential diagnostic significance. These antigens and their cognate autoantibodies could be considered as valuable targets for further analysis as poten...

Medullary breast carcinoma (MBC) is a relatively rare malignancy with heavy lymphocytic infiltration that despite cytologically anaplastic features and high mitotic index has more favorable prognosis than other types of breast cancer. Lymphocytic infiltration of tumors reflects ongoing immune response against tumor antigens which could represent a great interest as potential targets for cancer immunotherapy. The search for MBC antigens by SEREX methodology has not been successful due to a very high titer of false positive clones, representing immunoglobulin genes. Here, we describe a novel approach for generating cDNA expression libraries from MBC tumor samples which are depleted of IgG cDNA clones and, therefore, are suitable for the identification of novel tumor-associated antigens (TAA) by SEREX approach. Modified methodology allowed us to isolate a panel of known and novel TAA which are currently under further investigation.

Medullary breast carcinoma (MBC) despite anaplastic features and high grade has a good prognosis that can be related to prominent lymphocytic infiltration. We analyzed the frequency of antibody response toward 41 SEREX (serological recombinant expression cloning)-defined MBC antigens in sera of allogeneic MBC patients using serological plaque-spot assay and examined the mRNA expression profile of some antigens in MBC tissues. This preliminary study allowed us to select 18 autoantigens as potential MBC-associated antigens. Further studies in large cohorts of breast cancer patients will be performed for their evaluation as targets for cancer diagnostics or therapy.

In this study we describe the identification of sodium-dependent phosphate transporter NaPi2b as MX35 cancer-associated antigen. To achieve this goal we have screened extensively a cDNA expressing library from ovarian cancer cell line OVCAR3 with monoclonal antibody MX35. To further confirm the authenticity of this finding, we showed that bacterially and baculovirally expressed NaPi2b is specifically recognized by MX35 antibody. Moreover, the validity of these results was verified in a parallel study involving affinity purification and mass spectrometry. The epitope for MX35 monoclonal antibody was mapped to the largest extracellular loop of NaPi2b. Taken together, this study uncovers the identity of MX35 antigen and provides molecular tools for studying its function in normal and cancer tissues. Натрій-залежний транспортер NaPi2b ідентифіковано як MX35 пухлинний антиген. Для цього здійснено скринування кДНК-експресуючої біблеотеки, отриманої з клітин OVCAR3, моноклональними антитілами MX35. Щоб підтвердити ці дослідження, встановлено, що NaPi2b, експресований в бактеріях та клітинах комах, специфічно розпізнається MX35 антитілами. Крім того, виявлено ділянку, яка містить епітоп для моноклональних антитіл на великому позаклітинному домені NaPi2b. Таким чином, нами визначено антиген MX35, що забезпечує молекулярну основу для подальшого вивчення його функції в нормальних тканинах та при раку. Натрий-зависимый транспортер NaPi2b идентифицирован как MX35 опухлевый антиген. Для достижения этого осуществлено скринирование кДНК-экспрессирующей библиотеки, полученной из OVCAR3 клеток, моноклональными антителами. Чтобы подтвердить эти результаты, установлено, что NaPi2b, экспрессированный в бактериях и в клетках насекомых, специфично узнается антителами MX35. Определен участок на внеклеточном домене NaPi2b, содержащий эпитоп для антител. Таким образом, нами идентифицирован антиген MX35, что создает молекулярную основу для дальнейшего изучения его функции в нормальных и раковых тканях.

Background On the past decade a plethora of investigations were directed on identification of molecules involved in breast tumorogenesis, which could represent a powerful tool for monitoring, diagnostics and treatment of this disease. In current study we analyzed six previously identified medullary breast carcinoma autoantigens including LGALS3BP, RAD50, FAM50A, RBPJ, PABPC4, LRRFIP1 with cancer restricted serological profile in different histological types of breast cancer. Methods Semi-quantitative immunohistochemical analysis of 20 tissue samples including medullary breast carcinoma, invasive ductal carcinoma, invasive lobular carcinoma and non-cancerous tissues obtained from patients with fibrocystic disease (each of five) was performed using specifically generated polyclonal antibodies. Differences in expression patterns were evaluated considering percent of positively stained cells, insensitivity of staining and subcellular localization in cells of all tissue samples. Results All 6 antigens predominantly expressed in the most cells of all histological types of breast tumors and non-cancerous tissues with slight differences in intensity of staining and subcellular localization. The most significant differences in expression pattern were revealed for RAD50 and LGALS3BP in different histological types of breast cancer and for PABPC4 and FAM50A antigens in immune cells infiltrating breast tumors. Conclusions This pilot study made possible to select 4 antigens LGALS3BP, RAD50, PABPC4, and FAM50A as promising candidates for more comprehensive research as potential molecular markers for breast cancer diagnostics and therapy. Virtual slides The virtual slides’ for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1860649350796892