Lower grade astrocytomas most often relapse and proceed towards the more malignant grade.
Noteworthy, the polyclonal antibody used in the present study recognizes all survivin splice variants, and decreased nuclear survivin expression score was found among more malignant grade III cases of canine OSA, as well as higher nuclear survivin expression appeared to be related to a longer post-treatment OS, similarly to that observed by Trieb et al. [ 30] in the human counterpart.
Pilocytic astrocytomas only very seldom progress to a more malignant form, with the vast majority, even after multiple recurrences, maintaining their morphology and WHO grade I designation.
Higher tumour grade is also associated with an increase in the geminin/Ki67 ratio, signifying a shortening of G1 phase for the more malignant phenotype (grade 1: 0.29 vs grade 3: 0.36; P=0.07) and an increase in HER-2 expression (P=0.05).
We observed that the number of commonly under- or overexpressed genes in AS II, AS III and GBM IV were substantially increased in comparison to any intersection of PA I with two more malignant astrocytoma grades (Fig. 3 a– b, e.g. 1140 under- and 831 overexpressed genes in common between AS II, AS III and GBM IV vs. 27 under- and 62 overexpressed genes in common between PA I, AS II and GBM IV).
Molina-Pinelo et al (2011) recently reported an absence or reduced levels of Spn in nearly 60% of human lung tumours and found that the decreased Spn levels correlated with a more malignant tumour grade.
EGFR overexpression in tumor cells can produce up to 2 million EGFR molecules per cell, and has been correlated to a more malignant tumor grade as well as a reduced patient survival [ 48, 49].
This also implies the possibility that the increased accumulation of Survivin in cytoplasm opposes apoptotic death in the early less-malignant glioma cells and thus may provide a selective advantage and acceleration of progression from a lower grade glioma into a higher grade more malignant phenotype.
These are not more malignant than the average grade of the other true positives.
Occasionally keratin expression changes, especially when there is a change in differentiation; some of these exceptions include some of the higher-grade and more malignant cancers.
