[gdpawel]

What Chelle had was a molecular profiling assay. It is not considered a cellular profiling assay.

Target Now uses molecular profiling techniques, including both DNA microarray and immunohistochemical (IHC) analysis, to provide individualized information about a patient's tumor as an aid to the treating oncologist.

It uses IHC analysis with a patient's frozen tissue sample. it may also run a gene expression analysis by microarray which looks for genes in the tumor that are associated with specific treatment options.

Sometimes they utilize living cells, but generally of individual cancer cells in suspension, sometimes derived from tumors and sometimes derived from CTCs. This was tried with the old human clonogenic assay, which had been discredited long ago.

The endpoints (point of termination) of molecular profiling are gene expression, examining a single process (pathway) within the cell or a relatively small number of processes (pathways), to test for "theoretical" candidates for targeted therapy.

All DNA/RNA-type tests are based on "population" research (not individuals). It bases predictions on the fact that a higher percentage of people with similar genetic profiles or specific mutations may tend to respond better to certain drugs. This is not personalized medicine but a refinement of statistical data.

There is a problem with growing or manipulating tumor cells in any way. When looking for cell-death-related events, which mirror the effect of drugs on living tumors, cells are generally not grown or amplified in any way. The object is occurrence of programmed cell death in cells that come into contact with therapeutic agents.

Detectable tumor cells in peripheral blood are present only in extremely small numbers. This precludes allowing a sufficient number of cells to incubate for a few days in the presence of chemotherapeutic agents. Analysis of a relatively small number of isolated cancer cells cannot yield the same quality information as subjecting living cells to chemotherapeutic agents, begging the question of whether or not it can accurately predict which drugs will work and which will not.

The particular sequence of DNA that an organism possess (genotype) does not determine what bodily or behaviorial form (phenotype) the organism will finally display. Among other things, environmental influences can cause the suppression of some gene functions and the activation of others. Our knowledge of genomic complexity tells us that genes and parts of genes interact with other genes, as do their protein products, and the whole system is constantly being affected by internal and external environmental factors.

The gene may not be central to the phenotype at all, or at least it shares the spotlight with other influences. Environmental tissue and cytoplasmic factors clearly dominate the phenotypic expression processes, which may in turn, be affected by a variety of unpredictable protein-interaction events. This view is not shared by all molecular biologists, who disagree about the precise roles of genes and other factors, but it signals many scientists discomfort with a strictly deterministic view of the role of genes in an organism's functioning.