Oncogenesis • Human cancer development is a result of a genetic disease • protoncogenes • Tumour suppressor genes. • Regulatory expression of these genes can be seen in the normal cells and protein products of these genes are fundamental for normal cell function.
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Oncogenesis
• Human cancer development is a result of a genetic disease
• protoncogenes• Tumour suppressor genes.• Regulatory expression of these genes can be
seen in the normal cells and protein products of these genes are fundamental for normal cell function.
Examples:
• Oncogenes:
Ras, Myc, EGFR,c-erbB1,2,3.
• Tumour suppressor genes:
p53, Rb genes
Carcinogenesis• Multifactorial etiology.
• The tumour suppressor genes or oncogenes would be altered in the presence of carcinogens:
• Deletion : Loss of tumour suppressor genes • Mutation :p53, Ras• Inversion :Relocate the the oncogenes in• Translocation to DNA areas which will leads
inappropriate transcription.
• Subsequent accumulation of such growth promoting genetic defects forms the basis of current multi step process of tumourigenesis.
• This multi step process includes.
Initiation.
Promotion.
Tumour progression.
• Many of the known oncogenes and oncosupressor genes help control mitosis and apoptosis.
• Lack of this control would leads to development of malignancy.
• Genetic disease.
Tumour marker
• Substance or group of substance produced by the tumour
• Which can be used as a indicator to detect the presence of the tumour.