Analysis of Olig2 and YKL-40 expression: a clinicopathological/immunohistochemical study for the distinction between subventricular zone II and III glioblastomas.

Glioblastomas (GBs) are the most common and lethal primary brain tumors in the adults. Glioblastomas originates either from astrocytes that have accumulated mutations and de-differentiated or from neural stem cells within the subventricular zone (SVZ) in close contact with the vasculature. Recently, several studies have hypothesized that gliomagenesis occurs in perivascular niches with highly invasive peripheral proliferating zones. The purpose of our study was to investigate the pathological and clinical significance of Olig2 and YKL40 immunoexpression in 152 GBs in relationship to the SVZ II and III. Olig2 expressions were successfully detected in 12 (15.58%) of 77 SVZ type II GBs and 16 (21.3%) of 75 SVZ type III GBs, respectively. YKL-40 expression was observed in 45 (58.4%) of 77 SVZ type II GBs and in 17 (22.6%) of 75 SVZ type III GBs, respectively. Stepwise multivariate Cox proportional hazards models were used, and the prognostic factors to significantly impact OS were: PFS < 54 weeks (HR: 5.86; CI: 3.02-11.33; p = 0.00); radiotherapy (HR: 0.34; CI: 0.18-0.60; p = 0.00); radio- and chemotherapy (HR: 0.05; CI: 0.03-0.10; p = 0.0), and YKL-40+ GBs (HR: 1.61; CI: 1.28-2.31; p = 0.01).

Prognostic significance of the markers IDH1 and YKL40 related to the subventricular zone.

Glioblastoma multiforme (GBM), a highly aggressive brain cancer characterized by uncontrolled proliferation, resistance to cell death, angiogenesis, and vascular edema, remains one of the deadliest types of cancer. The subventricular zone (SVZ) harbors cells with great proliferative potential, and the microenvironment within the SVZ is permissive to growth and proliferation. This neurogenic niche is suspected to be a vulnerable site for the origin of subtypes of GBM. The aim of our study was to determine the immunohistochemical expression of mIDH1 and YKL40 in relationship to the SVZ of GBMs. YKL40, also known as chitinase-like protein 1, is included as a mesenchymal marker and associated with a poor prognosis. The protein is a secreted inflammatory molecule with no chitinolytic activity. However, the mutation of IDH1 (mIDH1) has been found in the cytoplasm and peroxisomes of 70-80% of secondary GBMs. In our study we found that YKL40-positive GBM is significantly linked to SVZ types IV and V (p < 0.0001). Our results show the diversity among GBMs related to the SVZ, which should be considered in the design of future targeted therapies. There was a significant impact of patient age, mIDH1 positivity, SVZ type III, and chemoradiotherapy on overall survival.