I last wrote about ALK in June 2008. I first came upon it when sitting at the feet of Professor Dennis Wright who gave us weekly tutorials on lymphomas while I was working in Bournemouth. Anaplastic large cell lymphoma needs to be distinguished from Hodgkin's disease (both of which show CD30 positivity) and can be so distinguished because of a chromosomal translocation which produces the NPM-ALK fusion protein.
However ALK can have many other partners in lots of different cell types. The important thing about ALK is that it is a tyrosine kinase like Glivec and could be inhibited therapeutically.
In this week's New England Journal of Medicine there are a series of reports where this has happened. The new TKI (tyrosine kinase inhibitor) is called Crizotnib and the tumor it works in is non-small cell lung cancer. Like Glivec, its efficacy became apparent after a small phase I trial. This type of non-small cell lung cancer is a small subtype, comprising only 5.5%, but this might mean over 10,000 candidates a year in the USA alone. Most of this group are non-smokers with adenocarcinomas. They had mostly already had best available chemotherapy, so a 57% response rate in these patients is impressive. It is early days yet, but this represents another step along the pathway to tailored therapy for cancer.