In many cell types, growth factor stimulation triggers the formation of structures called circular dorsal ruffles (CDRs). CDRs are large, rounded ruffles on the upper cell membrane that serve as platforms for PI3K–PIP3–AKT protein signaling and probably play a role in cell growth. CDRs are present in some types of cancer cells, but it’s unclear whether they contribute to cancer development. To find out, researchers recently treated six cancer cell lines and one normal cell line with two growth factors: epidermal growth factor and insulin. Both growth factors induced CDR formation in the Hep3B hepatocellular carcinoma line, but not in normal liver cells, other hepatocellular carcinoma cells, breast cancer cells, or pancreatic cancer cells. Closer analysis confirmed that growth factor receptor proteins were recruited to the CDRs and that the PI3K–PIP3–AKT pathway was activated at the ruffles. When drugs were used to inhibit CDR formation, AKT activation was reduced, but not eliminated, indicating that a portion of the growth factor–induced AKT signaling was CDR-independent. Although further testing is needed, the results suggest that CDRs may contribute to abnormal signaling in some cases of hepatocellular carcinoma, providing potential therapeutic targets for this type of cancer.