Fast cell cycle analysis for intraoperative characterization of brain tumor margins and malignancy

Flow cytometry, although indispensable for the characterization of hematologic malignancies, has not been extensively evaluated in solid tumors. To date intraoperative pathology evaluation of frozen sections of tissue obtained during surgery is the gold standard for intraoperative diagnosis. We investigated the value of a modified rapid protocol for cell cycle analysis for the intraoperative characterization of intracranial lesions and their surgical margins. We investigated patients who underwent surgery for an intracranial lesion suspicious for a tumor. DNA analysis and frozen sections were performed on tumor samples that were taken during surgery. Thirty-one patients met the inclusion criteria for the study. There was a significant difference in G0/G1 phase between high-grade and low-grade tumors. Receiver operating characteristic (ROC) analysis provided 75% of G0/G1 fraction as the optimal cutoff value thresholding the discrimination between low and high-grade tumors. There was a significant difference in S-phase and mitoses fraction between high-grade and low-grade tumors. ROC analysis indicated 6% of S-phase and 9.7% of mitoses as the optimal cutoff values thresholding the discrimination between these two groups. In the glioblastoma patients, we also analyzed the perilesional tissue and found significant differences between tumor mass and margins regarding the G0/G1 phase, the S-phase and mitoses fraction. In conclusion rapid cell cycle analysis is a method capable of differentiating low from high-grade tumors and delineating tumor margins in gliomas. Thus, the role of cell cycle analysis in brain tumors warrants further investigation.