Virtually all forms of cancer have deregulated cell proliferation, and more profoundly so in high grade gliomas, to such an extent that death is almost always certain within a couple of months after clinical diagnosis. For decades, clinicians and researchers alike have relied heavily on conventional morphologic and immunohistochemical analyses of tumour proliferative capacity for prognostication and therapeutic decisions. Surprisingly, given the enormity of its clinical relevance, much of the proliferative analyses have been constrained on ‘qualitative’ and ‘quantitative’ protein expression. In the current era where genome-wide molecular profiling is fast becoming routine, much can be gained if proliferative capacity is directly profiled molecularly. In the present study, focus has been placed on laying the groundwork to make this possible. We demonstrate histopathologically the functional phenotypic divergence of a glioma tumour into proliferative and non-proliferative components, resolve the technical issues in fractionating the proliferative cells for their RNA, and consequently, manage to successfully characterise the molecular profile of the proliferative cells, and in doing so, revealed a novel outlook on intratumour heterogeneity as a function of proliferative capacity. Essentially, this establishes a practical methodology that has the potential to lay the foundation for new approaches to cancer therapy, and new avenues for biological discoveries.