Explains how normal cells become cancer cells, starting with the key processes of uncontrolled division, avoidance of apoptosis, angiogenesis and metastasis. It then covers protein kinases such as EGFR, HER2 and BRAF, growth factors including EGF and VEGF, and the difference between proto-oncogenes and oncogenes, with Ras as an example. The note closes with personalised medicine, covering molecular profiling, biomarkers, targeted therapies such as imatinib and trastuzumab, and its benefits and challenges, followed by four multiple-choice questions with answers.
Topic 61 of 70 in the MU Sofia syllabus for Biochemistry (Dental Medicine, Year 2). The free AceMed note covers it in 5 sections, about 657 words (5 min of reading), with 10 flashcards.
In this note
MOLECULAR MECHANISMS OF ONCOGENESIS
ONCOGENES AND PROTO-ONCOGENES
PRINCIPLES OF PERSONALIZED MEDICINE
MCQS
ANSWERS
MOLECULAR MECHANISMS OF ONCOGENESIS
Overview of Oncogenesis
Definition: Oncogenesis, or tumorigenesis, is the process through which normal cells transform into cancer cells.
Key Processes:
Uncontrolled Cell Division: Cancer cells proliferate without the normal regulatory mechanisms.
Avoidance of Apoptosis: Cancer cells evade programmed cell death.
Angiogenesis: Formation of new blood vessels to supply the tumour.
Metastasis: Spread of cancer cells to other parts of the body.
MOLECULAR MECHANISMS OF ONCOGENESIS
Protein Kinases
Role in Cell Signalling: Function: Protein kinases are enzymes that modify other proteins by adding phosphate groups (phosphorylation), which can activate or deactivate target proteins.
Significance in Cancer: Dysregulation of protein kinases can lead to uncontrolled cell growth and cancer.
Examples: Receptor Tyrosine Kinases (RTKs): Such as EGFR (Epidermal Growth Factor Receptor) and HER2, which, when mutated or overexpressed, can drive oncogenesis.
Serine/Threonine Kinases: Such as BRAF, which is involved in the MAPK/ERK signalling pathway and can be mutated in cancers like melanoma.
MOLECULAR MECHANISMS OF ONCOGENESIS
Growth Factors
Definition: Growth factors are proteins that stimulate cell proliferation, differentiation, and survival.
Role in Cancer:
Overproduction: Cancer cells may produce excessive amounts of growth factors.
Autocrine Signalling: Cancer cells may respond to their own growth factors, leading to uncontrolled growth.
Examples:
EGF (Epidermal Growth Factor): Binds to EGFR and promotes cell proliferation.
VEGF (Vascular Endothelial Growth Factor): Promotes angiogenesis, supplying the tumour with nutrients and oxygen.
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