Polysomy of Chromosomes 1 and/or 19 Is Common and Associated With Less Favorable Clinical Outcome in Oligodendrogliomas

Abstract

It is well established that the combined del(1)(p36) and del(19)(q13) is a positive prognostic molecular event in oligodendroglial tumors. However, very little is known about the frequency or impact of polysomy status for chromosomes 1/19. We examined 84consecutive pure oligodendrogliomas (68 World Health Organization [WHO] grade II and 16 WHO grade III) and analyzed them for del(1)(p36) and del(19)(q13) by fluorescent in situ hybridization. Polysomy status was recorded with accompanying deletion status, WHO grade, recurrence-free survival, and overall survival. Codeletion of 1p/19q was detected in 48% of cases and correlated with superior patient survival (p < 0.01), as expected. Of 84 cases, 36 (43%) showed polysomy of chromosome 1, 30 (36%) demonstrated polysomy of chromosome 19, and 28 (33%) had copolysomies of chromosomes 1/19. The presence of polysomy of either/or both chromosomes, regardless of deletion status, correlated with younger patient age at initial diagnosis (p < 0.01). Combined polysomy was associated with higher histologic tumor grade (p = 0.04) and conferred poor survival likelihood (p = 0.03). We conclude that polysomy of 1 and/or 19 is a relatively frequent occurrence in oligodendrogliomas and usually confers an unfavorable outcome.

Polysomy of chromosomes 1 and 19: an underestimated prognostic factor in oligodendroglial tumors

“…Similarly, a lower occurrence of 19p polysomy was observed in WHO grade II gliomas. It was consistent with Wiens et al [14] report which maintained that polysomies of chromosomes 1 and/or 19 were slightly more common in high-grade tumors (56 % of AO vs. 42 % of O) and co-polysomy was significantly correlated with higher histologic tumor grade (P = 0.04).…”

“…But the frequency of 1q and 19p polysomy was significantly higher in mixed glioma compared with OGDs or astrocytic tumors. In 2012, Wiens et al [14] analyzed 84 consecutive pure oligodendrogliomas and found that the 1q and 19p polysomy rate was 43 and 36 %, respectively. They concluded that polysomy of 1q and/or 19p was a relatively frequent occurrence in oligodendrogliomas.…”

“…A similar tendency was observed in OS, but the difference was not statistically significant due to the smaller cohort (P = 0.303). Wiens et al [14] reported that polysomy of 1q and/or 19p was associated with less favorable clinical outcome (P = 0.06, P = 0.09, and P = 0.03, respectively), regardless of histological tumor grade. However, it was still unclear why patients with polysomy exhibited poorer outcome.…”

Renal cell carcinoma with angioleiomyoma-like stroma: clinicopathological, immunohistochemical, and molecular features supporting classification as a distinct entity

“…The cutoff value for 3p deletion was defined as a 3p25/CEP3 ratio of r0.7, as previously described. 7,18,[22][23][24] Definitions of chromosomal trisomy of chromosomes 7 and 17 were based on the Gaussian model and related to the nonneoplastic controls. The cutoff values for each probe were set at mean plus three standard deviations (mean þ 3 s.d.)…”

FISHing Tips: What Every Clinician Should Know About 1p19q Analysis in Gliomas Using Fluorescence in situ Hybridisation

“…Polysomy is more common in high-than low-grade gliomas [42e45], but data on its prognostic relevance independent of WHO grade are conflicting [44,45]. Few studies have evaluated the significance of polysomy in those with 1p19q co-deletion, with reports of both worse [45,46] and equivalent [21,47,48] survival compared with those without polysomy.…”