Original article Loss of genetic material within 1p and 19q chromosomal arms in low grade gliomas of central nervous system

Abstract

Loss of genetic material within 1p and 19q chromosomal arms in low grade gliomas of central nervous system D Da an ni ie el l R Rę ęc cł ła aw wo ow wi ic cz z 1 1 , , M Mi ir ro os sł ła aw w S St te em mp pn ni ie ew wi ic cz z 1 1 , , W Wo oj jc ci ie ec ch h B Bi ie er rn na at t 2 2 , , J Ja an nu us sz z L Li im mo on n 3 3 , , P Pa aw we eł ł S Sł ło on ni ie ew ws sk ki i IntroductionThe definition of low grade glioma encompasses three types of WHO grade II tumours including: diffuse astrocytoma (DA), oligodendroglioma (OD), and mixed glioma -oligoastrocytoma (OA). They constitute up to 30% of all glial tumours of the central nervous system. Distinguishing between these three types may be challenging due to both subjectivity of pathologists' judgment and lack of reliable objective markers confirming the diagnosis. The WHO classification does not pro vide the exact cut-off values of the oligodendroglial Folia Neuropathologica 2013; 51/1 27 and astrocytic component between three aforementioned types of tumours. Thus, discrepancy among pathologists exists, some use a 50% threshold level for the oligodendroglial component in making the diagnosis of oligodendroglioma [31], whereas others use a 10% cut-off [15].Recent publications suggest that deletion of chromosomal arm 1p/19q may play such an indicative role in the diagnosis of low grade gliomas (LGG) [1,11].LGGs demonstrate a broad range of genetic disturbances. One of the frequent alterations is simultaneous deletion of the short arm of chromosome 1 and the long arm of chromosome 19 [9]. Although chromosome 19q deletion used to be regarded a feature of both oligodendrogliomas and astrocytomas, further studies have shown its predominance in the former group [28]. Both deletions of 1p/19q frequently occur together and are seldom found as a separate alteration [4,19,24]. It is estimated that frequency of concurrent 1p and 19q deletion approaches 70-80% in oligodendrogliomas, 30-50% in mixed gliomas and only 7-15% in astrocytomas [4,19,24]. The deletion of 1p/19q is referred to as the most common genetic abnormality observed in oligodendrogliomas. Therefore, 1p/19q deletion seems to be a reliable signature of this neoplasm.In addition, the deletion of 1p/19q is additionally a predictive factor in OD. Cairncross et al. demonstrated that 1p deletion is a marker of the tumour che mosensitivity to procarbazine, lomustine and vincristine scheme (PCV) and concurrent 1p/19q deletion is a positive factor for a longer time to progression in anaplastic oligodendrogliomas [7]. Additionally, the use of multivariate statistics showed that survival in patients with 1p/19q loss is statistically longer than in patients without this alteration. These results were confirmed by retrospective analyses based on clinical studies EORTC 26951 and RTOG 9402. Both proved that presence of co-deletion correlates with the extended time to progression and time do death in grade III [3,6] and grade II gliomas [12]. Moreover, the latter study disclosed beneficial response to chemotherapy in...

Prognosis of older patients with low-grade glioma: A retrospective study

“…With respect to 1p19q deletion status, overall survival was improved but was not significantly different [22]. Despite previous studies that indicate that median survival in patients with diagnosed 1p and 19q deletion is twice as long in comparison with patients in whom no deletion was observed, our study did not find such a significant difference [11].…”

Screening of Glioma Patients for 1p/19q Region with Fluorescent Probes

“…Moreover, Smith et al [21] have demonstrated that the association of 1p and 19q loss with prolonged survival is also evident in low-grade oligodendroglioma patients and that this association may be independent of PCV chemotherapy. Ręcławowicz1 et al [22] in his study proved that combined loss involving chromosomes 1p and 19q is a strong factor for better prognosis.…”

Prognostic factors for low-grade diffuse gliomas and approaches to their treatment

“…Олигодендроглиальные опухоли (ОДО) считаются более благоприятными, чем астроцитарные, особенно при наличии характерной для ОДО транслокации 1p19q: медиана ОВ больных с ГНСЗ при наличии данной мутации вдвое выше, чем при ее отсутствии (80 мес против 41 мес) [6]. В свою очередь ДА, самая частая опухоль ВОЗ grade II, делится на несколько гистологических подтипов: фибриллярная астроцитома встречается у 65,2% больных, протоплазматическая -у 5,8% и гемистоцитарная -у 29%.…”