Final answer:
Mutations in the Ras protein that inhibit its GTPase activity cause excessive and unregulated cell proliferation, leading to cancer. This malfunction results in the Ras protein remaining active, constantly promoting cell division.
Step-by-step explanation:
Malfunctions in Ras protein signal transduction can lead to cancer through mutations that inhibit its GTPase activity. This results in the protein being perpetually activated, constantly signaling cell division and proliferation without regulation. When the Ras protein cannot hydrolyze GTP into GDP, it disregards the cell's normal growth checks, leading to uncontrolled cell division and potentially to tumor formation and cancer.
Mutations in the Ras gene, characterized as an oncogene, are responsible for approximately 30% of all cancers. The inability to switch off the Ras protein's signal for cellular proliferation due to disrupted GTPase activity highlights the link between this malfunction and the pathogenesis of cancer.