Which oncogene encodes the stem cell growth factor receptor and is associated with GI stromal tumors?

Which oncogene encodes the stem cell growth factor receptor and is associated with GI stromal tumors?

• A. c-kit
• B. BRAF
• C. c-myc
• D. BCR-ABL

Answer: (A)

The fundamental idea here is that a specific receptor tyrosine kinase drives many GI stromal tumors. GI stromal tumors almost always originate from interstitial cells of Cajal and commonly harbor activating mutations in the receptor tyrosine kinase encoded by c-kit. This gene encodes the stem cell factor receptor (CD117); when mutated, the receptor becomes constitutively active, promoting continuous signaling and tumor cell growth. That connection—c-kit as the receptor for stem cell factor and its role in GIST—is why this gene is the correct choice. These tumors often stain for CD117 and respond to imatinib, a drug that inhibits this tyrosine kinase. The other genes don’t encode the stem cell factor receptor: BRAF is part of the MAPK pathway but not the SCF receptor, c-myc is a transcription factor, and BCR-ABL is a fusion kinase seen in certain leukemias.

The fundamental idea here is that a specific receptor tyrosine kinase drives many GI stromal tumors. GI stromal tumors almost always originate from interstitial cells of Cajal and commonly harbor activating mutations in the receptor tyrosine kinase encoded by c-kit. This gene encodes the stem cell factor receptor (CD117); when mutated, the receptor becomes constitutively active, promoting continuous signaling and tumor cell growth. That connection—c-kit as the receptor for stem cell factor and its role in GIST—is why this gene is the correct choice. These tumors often stain for CD117 and respond to imatinib, a drug that inhibits this tyrosine kinase. The other genes don’t encode the stem cell factor receptor: BRAF is part of the MAPK pathway but not the SCF receptor, c-myc is a transcription factor, and BCR-ABL is a fusion kinase seen in certain leukemias.