As a student, he was encouraged to apply for the Oklahoma Medical Research Foundation's Sir Alexander Fleming Scholar Program which he described as having a "huge impact on my life.
[4][5] The following year, Armstrong published a landmark study in Nature Genetics which demonstrated that mixed-lineage leukemia (MLLs) exhibited a unique expression signature.
[7] As a result of his genome-wide technologies to characterize the molecular pathways responsible for leukemia development, Armstrong was elected a member of the American Society for Clinical Investigation[8] and was the recipient of the 2011 Paul Marks Prize for Cancer Research.
[7] Later that year, his research team collaborated with a biotechnology company to develop a drug that could deactivate cancer-promoting genes and halt the growth of cancer.
As a result of his "exceptional work in leukemia research and cancer stem cell biology," Armstrong was the recipient of the 2014 American Society of Hematology William Dameshek Prize.