1) These are two independent studies. Our Cancer Research paper published a little late with much more comprehensive studies and new mechanisms (March 2008), while the Cancer Letter paper was published a little early (December 2007).
2) The paper in Cancer Research was submitted and accepted before the Cancer Letter paper was published in December 2007 (see papers for detail dates). Therefore, it is impossible for us to know other groups are also working on similar studies and to acknowledge their work. It is also common that different groups carry out similar studies independently and publish the data subsequently in different journals.
3) The studies were initiated in 2006, which includes testing the drug activity in animal tumor models. The work was first submitted to another high profile journal in September 2007, almost at the same time as the Cancer Letter paper submission date.
4) The coauthors published their first GA paper in Blood in August 2007 (Blood. 2007 Nov 15;110(10):3517-25. Epub 2007 Aug 2).

Therefore, the accusation is misleading and irresponsible, especially ignoring the close publication dates and only stating 2007 and 2008 for the two independent studies.