When epidermal growth factor (EGF)—the ligand for the epidermal growth factor receptor (EGFR)—binds EGFR
on the cell surface, the intracellular domain of the
receptor changes shape into an "active state." The
receptor then induces a cascade of kinases in the
cytoplasm, resulting in the activation of mitogen-
activated protein kinase (MAPK). One effect of EGFR
signaling is the stimulation of cell proliferation.
Overactive EGFR is frequently found in cancer cells.

One strategy for developing anticancer drugs is to target
the overactive signaling proteins found in cancer cells.
Antibodies are proteins made by immune cells that only
recognize specific biomolecules, called antigens.

The
major component of an anticancer drug is an antibody
that specifically recognizes and binds EGFR.

Which of the following will most likely happen when this
anticancer drug is applied to a tumor that has a high level
of EGFR?

O Tumor cells with active EGFR will increase and
MAPK activity in the tumor will increase.
OTumor cells with active EGFR will decrease and
MAPK activity in the tumor will increase.
O Tumor cells with active EGFR will increase and
MAPK activity in the tumor will decrease.
O Tumor cells with active EGFR will decrease and
MAPK activity in the tumor will decrease.