We start our quest assuming an implicit working hypothesis common to many research groups around the world: the macroscopic physiological changes (i.e. Hanahan and Weinberg's ''hallmarks'') must also correlate with global alterations of the molecular profiles of gene transcription. It is also assumed that the ''hallmark changes'' occur along a certain timeline, but that some of the sub-processes discussed before are concurrent. These processes may start in a slow incremental way with some of the major changes being early events while others (e.g. tissue invasion and metastasis) are likely later processes triggered by new events during cancer progression. The timeline is not explicit and it is also likely that cancer subtypes progress to similar timelines. In some cases the sequence of events are better understood (e.g. some leukaemia subtypes [39] ). The elicitation and regulation of molecular events is likely to be an ongoing quest during this century for many types of cancer.