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• 1p 19q deletion in grade III oligodendroglial tumors and radiological markers.
  Ricardo Prat Ac?n
  Published on: 13 April 2016
• Anaplastic oligodendroglial tumors: Do gray matter involvement correlate with 1p19q codeletion?
  Gentian Kaloshi
  Published on: 13 April 2016

• Published on: 13 April 2016

  1p 19q deletion in grade III oligodendroglial tumors and radiological markers.

  • Ricardo Prat Ac?n, Neurosurgery Prof
  • Other Contributors:
    • Inmaculada Galeano, Giovanni Pancucci, Angel Ayuso-Sacido

  We read with interest the work by Kim et al that shows relationship between radiological characteristics and molecular signatures in a group of 49 patients with anaplastic oligodendroglioma (AO) and 7 patients with anaplastic oligoastrocytoma (AOAs). Frontal lobe location, indistinct tumor borders and heterogeneous intratumoral signal intensity were significantly correlated with the 1p19q codeletion. It has been previous...

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  We read with interest the work by Kim et al that shows relationship between radiological characteristics and molecular signatures in a group of 49 patients with anaplastic oligodendroglioma (AO) and 7 patients with anaplastic oligoastrocytoma (AOAs). Frontal lobe location, indistinct tumor borders and heterogeneous intratumoral signal intensity were significantly correlated with the 1p19q codeletion. It has been previously published the existence of molecular heterogeneity associated to location in oligodendroglial tumors showing an increased frequency of 1p19q codeletion in frontal lobe location whereas temporal lobe location associated greater number of patients lacking 1p19q codeletion. Previous works also describe decreased chemosensibility of AO located in temporal lobe, insula and diencephalus. The authors try to conclude that high-grade oligodendroglial tumors (AO/AOAs) share a similar relationship between radiological characteristics and molecular signatures as in oligodendroglial tumors. We would like to add further comments to these issues. First, the limited number of patients and doubtful tumoral anatomical location (eleven tumor cases were located in multiple lobes) should make see the results cautiously. Previous published experiences report loss of heterozygosity for 1p and 19q to be significantly associated with a bilateral pattern of growth [1], but Kim et al do not refer to bilateral pattern in their paper, nor clearly define multiple location, and only report 4 patients with parieto-occipital lesion and 11 with temporoinsular location. Second, we would like also to raise the question of patient selection: management of low grade glioma is very heterogeneous including total/subtotal removal of the lesion with functional boundaries, biopsy and even "wait and see" attitude. In our opinion, only complete or near complete removal of low grade glioma can give complete information of the histological diagnosis, since it is our experience that anaplastic transformation loci, and astrocytic component can be seen after expanded removal in a previously so called low grade lesion or oligodendroglial lesion without astrocytic component. Third, the authors report intratumoral heterogeneous to be favorable sign for patient survival and also that this signal may result from intratumoral haemorrhage, necrosis or calcification. The 2009 EORTC prospective randomized study on molecular analysis of anaplastic oligodendroglial tumors [2], report both necrosis, and 1p(loss)19q(loss) to be independent prognostic factors. Since necrosis has a profound impact on survival, a more refined description of intratumoral heterogeneity could help to establish the association between both radiological and molecular characteristics. Fourth, we read with surprise that no significant relationship between 1p19q codeletion and tumor enhancement is found in the present series. Around 20% of AO have the enhancement pattern, which is statistically correlated with frequent recurrence, indeed, some series report not to have found combined 1p/19 loss in any of the cases with anaplastic oligodendrogliomas with enhancement pattern [3]. Although quite interesting, the study has several limitations, particularly its retrospective nature. Further prospective studies including larger numbers of cases and standardized evaluation of 1p19q codeletion in conjunction with other relevant prognostic parameters are needed to draw definitive conclusions on the issue of radiological markers for molecular signatures in grade III oligodendroglial tumors 1. Zlatescu MC, TehraniYazdi A, Sasaki H, et al. Tumor location and growth pattern correlate with genetic signature in oligodendroglial neoplasms. Cancer Res 2001; 61:6713-15. 2. Kouwenhoven MC, Gorlia T, Kros JM, et al. Molecular analysis of anaplastic oligodendroglial tumors in a prospective randomized study: A report from EORTC study 26951. Neuro Oncol 2009; 11:737-46. 3. Young Choi, Tae-Young Jung, Shin Jung, et al. Prognosis of oligodendroglial tumor with ring enhancement showing central necrotic portion. J Neurooncol 2011; 103:103-110

  Conflict of Interest:

  None declared

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  Conflict of Interest:
  None declared.

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• Published on: 13 April 2016

  Anaplastic oligodendroglial tumors: Do gray matter involvement correlate with 1p19q codeletion?

  • Gentian Kaloshi, Neurologist
  • Other Contributors:
    • Mentor Petrela

  Gentian Kaloshi, Mentor Petrela

  In their recently published article, Kim et al (1) describe the imaging characteristics of anaplastic oligodendroglioma and anaplastic oligoastrocytoma (AO/AOAs) in an effort to correlate them with molecular alterations. They try to conclude that high-grade oligodendroglial tumors (AO/AOAs) share a similar relationship between radiological characteristics and molecular signatures...

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  Gentian Kaloshi, Mentor Petrela

  In their recently published article, Kim et al (1) describe the imaging characteristics of anaplastic oligodendroglioma and anaplastic oligoastrocytoma (AO/AOAs) in an effort to correlate them with molecular alterations. They try to conclude that high-grade oligodendroglial tumors (AO/AOAs) share a similar relationship between radiological characteristics and molecular signatures as in oligodendroglial tumors. More specifically, they found that 1p19q codeleted AO/AOAs involved the frontal areas more frequently, were more frequently bilateral with a tendency towards widespread growth across the midline, and had poorly delineated limits in T1 with irregular aspect in T2. However, they failed to find any association of molecular alterations with contrast enhancement, cortical involvement and other radiological features such as calcification, hemorrhage, cystic formation.

  We challenge their findings. Gliomatosis have taught us that tumors with 1p19q loss involve the white matter more frequently than other tumors, suggesting that this radiological characteristic can be related to intrinsic differences in tumor cells and, perhaps, to the different microenvironnement between gray matter and white matter. (2)

  In the report of Kim et al, eleven tumor cases were located in multiple lobes making the diagnosis of gliomatosis most probable. Consequently, in our opinion, it would be very useful to further investigate if AO/AOAs share also the same clinical and radiological correlation of gliomatosis. Moreover, the figure 1 in their article is a good example of radio-genetic relationship found in gliomatosis.

  How can these studies be reconciled in our daily practice? Surely, the most likely impact is that radiological characteristics may be considered as phenotype of intrinsic characteristics of tumors. Thus, they may have prognostic value as a surrogate marker for molecular alterations.

  References:

  1. Kim JW, Park CK, Park SH, et al. Relationship between radiological characteristics and combined 1p and 19q deletion in World Health Organization grade III oligodendroglial tumours. J Neurol Neurosurg Psychiatry 2011; 82: 224-227

  2. Kaloshi G, Guillevin R, Martin-Duverneuil N, et al. Gray matter involvement predicts chemosensitivity and prognosis in gliomatosis cerebri. Neurology 2009;11;73(6):445-9.

  Conflict of Interest:

  None declared

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  Conflict of Interest:
  None declared.

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