"The systematic characterization of somatic mutations in cancer genomes is essential for understanding the disease and for developing targeted therapeutics."
So began today's journal article from a letter to Nature (link below) from scientists at Genentech. They went on to state that they have looked at:
"The identification of 2,576 somatic mutations across 1,800 megabases of DNA representing 1,507 coding genes from 441 tumours comprising breast, lung, ovarian and prostate cancer types and subtypes. We found that mutation rates and the sets of mutated genes varied substantially across tumour types and subtypes.
Statistical analysis identified 77 significantly mutated genes including protein kinases, G-protein-coupled receptors such as GRM8, BAI3, AGTRL1 (also called APLNR) and LPHN3, and other druggable targets.
Integrated analysis of somatic mutations and copy number alterations identified another 35 significantly altered genes including GNAS, indicating an expanded role for Ga subunits in multiple cancer types."
The goal of this type of analysis is to look for patterns and alterations associated with disease and try to figure out which are potentially druggable targets for drug development. The researchers went on to note:
"Our study represents a substantial expansion of the knowledge base of cancer somatic mutations. Of the 845 genes with proteinaltering mutations identified in this study, 361 (43%), including 13 significantly mutated genes like TLR4, SPOP and NRG3, have not previously been reported."
That's great news. Of course, it should be noticed that theory is one thing, but until a pipeline compound enters into clinical trials and we see the results of extensive studies, we won't know whether the target is truly a relevant one in human cancers or not.
Not all mutations may occur in every person though, as we have seen in lung cancer where some people might have an EGFR mutation, some an ALK mutation and so on. The secret to this approach is to start documenting the likely targets and go looking to see how many exist, which ones might be a critical driver and which ones are merely passengers.
Clearly though, it does help to have an idea of what the needles in the haystack might look light before going hunting for them to increase the chances of success.
Photo Credit: Yellow Book
Kan, Z., Jaiswal, B., Stinson, J., Janakiraman, V., Bhatt, D., Stern, H., Yue, P., Haverty, P., Bourgon, R., Zheng, J., Moorhead, M., Chaudhuri, S., Tomsho, L., Peters, B., Pujara, K., Cordes, S., Davis, D., Carlton, V., Yuan, W., Li, L., Wang, W., Eigenbrot, C., Kaminker, J., Eberhard, D., Waring, P., Schuster, S., Modrusan, Z., Zhang, Z., Stokoe, D., de Sauvage, F., Faham, M., & Seshagiri, S. (2010). Diverse somatic mutation patterns and pathway alterations in human cancers Nature DOI: 10.1038/nature09208