**8. Technology and chemical carcinogenesis**

Many technological advances have allowed conceptual ideas to be experimentally tested, including the sensitive detection of chemical carcinogens by high-pressure liquid chromatography (Esaka, et al., 2003) and mass spectrometry (Sigh and Farmer,2006), detection of DNA adducts by postlabeling (Randerath et al, 1981) and by specific antibodies (Poirier et al., 1977), transcriptional profiling by arrays ( Kallioniemi et al., 1992, Schena et al., 1995), and quantitation of mutagenicity of carcinogens using bacterial genetics (Ames et al., 1973). The testing of certain concepts in chemical carcinogenesis awaited the development of new technologies. For example, the concept of somatic mutations in cancer preceded by 40 years the establishment of DNA as the genetic material and by 67 years the development of DNA sequencing methods that directly showed clonal mutations in human cancer cells. Also, the mutator phenotype hypothesis formulated in 1974 has been only recently experimentally verified. The list below shows some commonly employed analytical techniques requiring the attention of biomedical engineering and technology.

Some analytical areas that may be particularly relevant in chemical carcinogenesis will include:


The latter is particularly promising as it enables the simultaneous measurement of transcription of thousands of genes using microchips containing thousands of probes of complementary DNA (cDNA) immobilized in predetermined array. But suffers the caveat of being very expensive especially for the developing countries that appear to be mostly in need of it currently.
