April 2012
- LRG mourns the loss of a great friend, Jeroen Pit
- GDOL Update: Speakers announced
- LRG Research Team meets in Leuven, Belgium: leaves with renewed energy & commitment to finding the cure for GIST
- Meet our new Montana local rep: Dirk Niebaum
- Cellular origin of GIST from the “good” cells’ perspective
- Alianza GIST meets in Miami
- And they’re off! 1st ‘Harness a Cure’ is a success
- NJ GIST gathering serves up support & smoothies
- NoCal GISTers meet!
- New report finds most hospital errors go unreported
- Happy Cancerversary to Brenda Bannon!
- Thomas G. Overley, 1952-2012: Toledo lawyer played guitar, sang in group
- Durham lived life with passion and pride
- Did You Hear? Did You Know?
- Arizona GISTers meet!
- Spunky Texan fought GIST bravely
- Calendar
Archive
July 2009
Evaluation of the presence of IGF1R over expression in wildtype and kinase mutant GI stromal tumors
Abstract 10506, Christopher Corless, MD, PhD, Oregon Health & Science University. Chris is a member of the LRG Research Team
Fifteen percent of adult patients and 90 percent of pediatric patients have wildtype GIST.
Corless presented data showing a wide degree of expression in IGF-1R levels in 114
patients with various GIST mutations including 51 wildtype cases. IGF-1R was not
expressed at high levels in patients with exon 11, PDGFRA or other GIST mutations. It
was expressed at high levels (30 times higher) in Pediatric wildtype GIST tumors and in a
subset (60%) of wildtype adult tumors. Interestingly, about 40 percent of adult wildtype
tumors show low expression levels typical of KIT/PDGFRA mutant GIST. In addition,
there was a subset of tumors with varying mutations that had low expression levels of
KIT, PDGFRA and IGF-1R.
Corless commented, “It is quite a heterogeneous mix. It implies a lot more biology going
on than we had previously appreciated.” (Editorial: In context this comment conveys the importance of wildtype tumors in discovering the diverse biology of GIST beyond KIT. The answers provided through study of wildtype tumors could eventually impact all GIST patients who face resistance. It also points out the need for wildtype tissue in a shared resource, like the GIST CollaborativeTissue Bank, where all Tissue Bank researchers have access.)
In a clinical response analysis on a subset of 24 Phase III imatinib trial wildtype tumors
the sample size was small but the numbers were “tantalizing”. Corless reported that there was an observable (but not yet significant) “trend” between high IGF-1R expression and less favorable response on imatinib. In these same tumors, high KIT expression was significantly correlated with good response to imatinib. This study adds to work done earlier by Dr. Cristina Antonescu at Memorial Sloan-Kettering Cancer Center (MSKCC)
and Dr. Andrew Godwin at Fox Chase Cancer Center. An IGF-1R inhibitor is not yet
approved, but multiple candidates are in trials worldwide. Corless anticipates that as these
studies get underway, additional data will further clarify these trends.
Abstract #: 10506
0 Comments