Last week, the U.S. Patent and Trademark Office issued U.S. Patent No. 8,623,601, which is entitled "Methods of diagnosing cancer." The '601 patent, which is assigned to Duke University and Cognosci, Inc. (out of the Research Triangle Park in North Carolina), contains claims to a method of predicting or assessing the level of severity of cancer or cancer progression in a patient diagnosed with chronic lymphocytic leukemia or B-cell non-Hodgkin's lymphoma.
The claimed method is based on the discovery that the levels of SET present in a biological sample and the ratio of SET protein isoforms SET a and SET ß in the biological sample can be measured and are prognostic indicators of cancer severity or progression. More specifically, the claimed method relies on measuring the levels of SET a and SET ß protein or RNA in B lymphocytes isolated from a blood sample of a patient diagnosed with chronic lymphocytic leukemia or B-cell non-Hodgkin's lymphoma where the inventor learned that CLL patients with high a/ß ratios had significantly shorter overall survival (~4 years shorter) than did patients with low a/ß ratios.
The SET protein is a multitasking protein, involved in apoptosis, transcription, nucleosome assembly, and histone chaperoning, and is known to be a potent physiological inhibitor of protein phosphatase 2A. The expression of the a and ß isoforms is driven by distinct promoters, and the isoforms differ only in the N-terminal portion of the protein in which the a-isoform has a 37 amino acid N-terminal region that arises from Exon 1 of the SET gene while the ß-isoform has a 24 amino acid N-terminal region that arises from Exon 2 of the SET gene. As the SET protein was isolated from a chromosomal rearrangement at 9q34 in a patient with acute undifferentiated leukemia, it makes sense that it can now be used in methods to predict the level of severity of some types of leukemia.
The patent has one independent claim that recites:
1. A method of predicting or assessing the level of severity of cancer or cancer progression in a patient diagnosed with chronic lymphocytic leukemia or B-cell non-Hodgkin's lymphoma comprising determining the ratio of SET alpha isoform to SET beta isoform in B lymphocytes isolated from the patient and comparing the ratio of SET alpha isoform to SET beta isoform to the ratio in a control sample or a standard value, wherein an increase in the ratio of SET alpha isoform to SET beta isoform relative to the ratio in the control sample or standard value is indicative of a more severe form of cancer or later stage of cancer progression in the patient.
As cancer is predicted to overtake heart disease as the leading cause of death, there is a continued need for advancing methods for predicting the severity of cancers. The '601 patent provides a method that would allow physicians to determine whether a particular leukemia patient would benefit from aggressive treatment or whether a less aggressive form of treatment is appropriate, which could improve the treatment strategy for the leukemia patient and may improve survival.