Cancer is a highly complex and heterogeneous disease involving a succession of 
genetic changes (frequently caused or accompanied by exogenous trauma), and 
resulting in a molecular phenotype that in turn results in a malignant 
specification. The development of malignancy has been described as a multistep 
process involving self-sufficiency in growth signals, insensitivity to 
antigrowth signals, evasion of apoptosis, limitless replicative potential, 
sustained angiogenesis, and finally tissue invasion and metastasis. The 
quantitative analysis of networking molecules within the cells might be applied 
to understand native-state tissue signalling biology, complex drug actions and 
dysfunctional signalling in transformed cells, that is, in cancer cells. 
High-content and high-throughput single-cell analysis can lead to systems 
biology and cytomics. The application of cytomics in cancer research and 
diagnostics is very broad, ranging from the better understanding of the tumour 
cell biology to the identification of residual tumour cells after treatment, to 
drug discovery. The ultimate goal is to pinpoint in detail these processes on 
the molecular, cellular and tissue level. A comprehensive knowledge of these 
will require tissue analysis, which is multiplex and functional; thus, vast 
amounts of data are being collected from current genomic and proteomic platforms 
for integration and interpretation as well as for new varieties of updated 
cytomics technology. This overview will briefly highlight the most important 
aspects of this continuously developing field.