Finally, the incidences of tumours in all the major morphological subgroups increased, as did that of tumours that were not histologically verified, although they continued to constitute a minor proportion of CNS tumours.
The incidence rate increased consistently for all morphological subgroups, except for the small subgroup of 'other gliomas'.
Thus, a British study showed a stable rate of ependymomas (McNally et al, 2001), one study in the USA showed a stable rate of primitive neuroectodermal tumours (Gurney et al, 1996) and another study in the USA, spanning 21 years, showed that increases in the incidence rates of various morphological subgroups depends on the period studied (Linet et al, 1999).
The variation of MIs within morphological subgroups was especially pronounced in high grade lymphomas.
Four hematologists (AI, DC, NO and FG) were then required to evaluate clinical features of the patients clustered in the three morphological subgroups identified by the multiple correspondence analysis.
The size of the database enabled very detailed survival analyses by age, sex, morphological subgroups and subsites.
In these studies subsets of genes differentially expressed in tumors could predict survival differences among patients with LAC within consistent morphological subgroups.
The aetiology is in most cases unknown, and likely to differ among the different morphological subgroups.
Examples of features from the morphological subgroup are Area Centroid, Major Axis Length, Whole Matter Volumes, etc. Examples of features from the mathematical subgroup are Mean, Cosine Transform Coefficients, Euclidean distance, etc.
Identification of fishes to morphological subgroup (C. temensis and remaining clade A species, C. orinocensis C. intermedia, or C. ocellaris and remaining clade B1 species), which are sympatric, was unambiguous at every locality.
