DNA content is associated with malignancy of intracranial neoplasms

Factors related to morbidity and mortality of meningiomas resection‑associated venous thromboembolism (Review)

Patients undergoing intracranial meningioma removal have been reported to have an increased risk of venous thromboembolism (VTE). The present study aimed to study meningioma operations and ascertain rates of postoperative VTE more closely and to find out the associated parameters with VTE-related morbidity and mortality in meningioma patients following resection. This meta-analysis included articles involving meningiomas surgery and postoperative VTE [thromboembolic complications: deep venous thrombosis (DVT) and pulmonary embolism (PE)] published in full-text form between January 1980 and January 2021). Collected variables included: First author name, study period covered, publication year, total number of patients and age, number of males, surgical duration, body mass index (BMI), tumor location, proliferation marker for human tumor cells Ki-67 and VTE-related morbidity and mortality. After the initial search and applying all exclusion and inclusion criteria, five articles were left in the final article pool. The total number of patients was 6,505 who underwent surgery for meningiomas and 299 (4.5%) revealed postoperative VTE. The final results showed no potentially significant difference between the total sample and the postoperative VTE group in tumor location and proliferation marker Ki-67 for human cells. By contrast, the results of the analysis for surgical duration and BMI showed a statistically significant difference. Patients who had experienced open surgery for meningiomas were associated with postoperative VTE. Furthermore, surgical duration and BMI were statistically significant VTE-related parameters in patients who underwent meningioma surgery, showing an association with VTE-related morbidity and mortality.

Assessment of Gliomas' Grade of Malignancy and Extent of Resection Using Intraoperative Flow Cytometry

BACKGROUND

Intraoperative Flow Cytometry (iFC) is a novel technique for the assessment of the grade of malignancy and the diagnosis of tumor type and resection margins during solid tumor surgery. Herein, we set out to analyze the role of iFC in the grading of gliomas and the evaluation of resection margins.

MATERIAL AND METHODS

iFC uses a fast cell cycle analysis protocol (Ioannina Protocol) that permits the analysis of tissue samples within 5-6 min. Cell cycle analysis evaluated the G0/G1 phase, S-phase, mitosis, and tumor index (S + mitosis phase fraction) and ploidy status. In the current study, we evaluated tumor samples and samples from the peripheral borders from patients with gliomas who underwent surgery over an 8-year period.

RESULTS

Eighty-one patients were included in the study. There were sixty-eight glioblastoma cases, five anaplastic astrocytomas, two anaplastic oligodendrogliomas, one pilocytic astrocytoma, three oligodendrogliomas and two diffuse astrocytomas. High-grade gliomas had a significantly higher tumor index than low grade gliomas (median value 22 vs. 7.5, respectively, p = 0.002). Using ROC curve analysis, a cut-off value of 17% in the tumor index could differentiate low- from high-grade gliomas with a 61.4% sensitivity and 100% specificity. All low-grade gliomas were diploid. From the high-grade gliomas, 22 tumors were aneuploid. In glioblastomas, aneuploid tumors had a significantly higher tumor index (p = 0.0018). Twenty-three samples from glioma margins were evaluated. iFC verified the presence of malignant tissue in every case, using histology as the gold standard.

CONCLUSION

iFC constitutes a promising intraoperative technique for glioma grading and resection margin assessment. Comparative studies with additional intraoperative adjuncts are necessary.

Advances in Intraoperative Flow Cytometry

Flow cytometry is the gold-standard laser-based technique to measure and analyze fluorescence levels of immunostaining and DNA content in individual cells. It provides a valuable tool to assess cells in the G0/G1, S, and G2/M phases, and those with polyploidy, which holds prognostic significance. Frozen section analysis is the standard intraoperative assessment for tumor margin evaluation and tumor resection. Here, we present flow cytometry as a promising technique for intraoperative tumor analysis in different pathologies, including brain tumors, leptomeningeal dissemination, breast cancer, head and neck cancer, pancreatic tumor, and hepatic cancer. Flow cytometry is a valuable tool that can provide substantial information on tumor analysis and, consequently, maximize cancer treatment and expedite patients’ survival.

The Past, Present and Future of Flow Cytometry in Central Nervous System Malignancies

Central nervous system malignancies (CNSMs) are categorized among the most aggressive and deadly types of cancer. The low median survival in patients with CNSMs is partly explained by the objective difficulties of brain surgeries as well as by the acquired chemoresistance of CNSM cells. Flow Cytometry is an analytical technique with the ability to quantify cell phenotype and to categorize cell populations on the basis of their characteristics. In the current review, we summarize the Flow Cytometry methodologies that have been used to study different phenotypic aspects of CNSMs. These include DNA content analysis for the determination of malignancy status and phenotypic characterization, as well as the methodologies used during the development of novel therapeutic agents. We conclude with the historical and current utility of Flow Cytometry in the field, and we propose how we can exploit current and possible future methodologies in the battle against this dreadful type of malignancy.

The emerging role of intraoperative flow cytometry in intracranial tumor surgery

Intraoperative flow cytometry has been recently emerged as a novel and promising tool for intracranial tumor surgery. Herewith, we discuss the role of intraoperative flow cytometry for the identification of gliomas boundaries, which may permit maximal resection and better prognosis. We also discuss its role in assessing tumor's grade of malignancy, both in adults and children and the prognostic information that may provide. Finally, intraoperative immunophenotypic analysis opens new horizons for flow cytometry. By evaluating tumor's specific cluster differentiation markers a diagnosis, within minutes, of certain tumor type can be achieved and additional information for therapeutic guidance can be provided.

Application of flow cytometry for evaluating clinical prognosis and histopathological grade of human glioma

OBJECTIVES

Flow cytometry was applied to predict the biological parameters of tumor behavior based on the DNA content distribution of tumors. We used flow cytometry to determine the number of cell cycles for the characterization of intracranial gliomas and its possible prognostic role.

METHODS

Flow cytometric analysis of the DNA content was performed for 37 fresh operative glioma specimens. The expression of Ki-67 in glioma specimens was detected using immunohistochemistry staining. The check points of G2/M-phase fractions, cyclin B, and pCdk1 (Y15) were analyzed using Western immunoblotting.

RESULTS

Compared to low-grade (grade I/II) gliomas, significant differences in the Ki-67, cyclin B, G2/M-phase, and S+G2/M-phase expressions were found in high-grade (grade III/IV) gliomas. Furthermore, receiver operating characteristic (ROC) analysis indicated optimal cutoff points for the G2/M-phase and S+G2/M-phase fractions of 13.47 and 17.26%, respectively, which can be used to differentiate cases with low- and high-grade gliomas. Additionally, both G2/M-phase and S+G2/M-phase fractions had significant association with the expression of Ki-67 in the gliomas. The gliomas were classified by the DNA content. We found that patients with high-grade glioma had worse survival rate than patients with low-grade glioma. Meanwhile, ROC curve analysis gave cutoffs for G2/M-phase of 9.4% and for S+G2/M-phase fractions of 15.04% as best predicting survival. The patients with glioma had poor survival when the levels of G2/M-phase and S+G2/M-phase were more than 9.4 and 15.04%, respectively. In contrast, no significant association between the DNA content of glioma patients and their age, tumor recurrence, and tumor size was found.

DISCUSSION

Our results indicate that flow cytometry analysis for G2/M-phase and S+G2/M-phase fractions can be used for tumor grading for rapidly differentiating low- from high-grade gliomas.

The Role of Fast Cell Cycle Analysis in Pediatric Brain Tumors

Cell cycle analysis by flow cytometry has not been adequately studied in pediatric brain tumors. We investigated the value of a modified rapid (within 6 min) cell cycle analysis protocol for the characterization of malignancy of pediatric brain tumors and for the differentiation of neoplastic from nonneoplastic tissue for possible intraoperative application. We retrospectively studied brain tumor specimens from patients treated at our institute over a 5-year period. All tumor samples were histopathologically verified before flow-cytometric analysis. The histopathological examination of permanent tissue sections was the gold standard. There were 68 brain tumor cases. All tumors had significantly lower G0/G1 and significantly higher S phase and mitosis fractions than normal brain tissue. Furthermore low-grade tumors could be differentiated from high-grade tumors. DNA aneuploidy was detected in 35 tumors. A correlation between S phase fraction and Ki-67 index was found in medulloblastomas and anaplastic ependymomas. Rapid cell cycle analysis by flow cytometry is a promising method for the identification of neoplastic tissue intraoperatively. Low-grade tumors could be differentiated from high-grade tumors. Thus, cell cycle analysis can be a valuable adjunct to the histopathological evaluation of pediatric brain tumors, whereas its intraoperative application warrants further investigation.