Week 13 CTL Notes
Cancer, Cell Death & Cellular Ageing
Growth Characteristics of Normal Cells:
• Subject to contact inhibition
• Limited lifespan esperanza de vida
→
• Anchorage dependant
• Growth-factor dependant
• Able to apoptose.
Growth Characteristics of Tumour & Cancer Cells:
• Not subject to contact inhibition
• Unlimited lifespan
• Anxhorage Independant
• Unresponsive to growth-inhibitors
• Unable to apoptose.
• Differentiate independently.
o Differentiated tumours = teratomas.
o May form teeth, hair, bone, nails, toes, brain matter etc.
General Characteristics of BENIGN TUMOUR CELLS:
• Lower mitotic index than cancerous tissue.
• Well-defined capsule
• NOT INVASIVE
• Well differentiated – still exhibit characteristics of their normal cells of origin.
• NOT METASTATIC
General Characteristics of METASTATIC CANCERS:
• Abnormally high mitotic rate
• Show signs of de-differentiation
o have features of primordial stem-cells
• Disordered growth patterns
o Grow as a chaotic mass in all directions
• Can be Metastatic (Colonise distant tissues)
o Cells can break away from primary
tumour & travel through blood/lymph.
o Establish new tumours (secondaries)
called metastases.
• Show gross genetic abnormalities.
o Aberration in chromosome number
o Deletions, translocations in genome
• Grow in the absence of growth factors.
• Are Immortal
o Escape cellular ageing (senescence)
o Many also don’t apoptose
• Malignant phenotype is heritable.
o Cancer cells propagate through many
mitotic divisions without losing cancerous features.
www.MedStudentNotes.com
, Cause of Cancer
• Genetic mutations that are non-lethal to the cell.
• Results from mutagens:
o Chemicals
o Radiation
o Carcinogens
o Free-Radicals
o Microbes (viruses)
o Inherited.
• DNA damage = dysregulated growth patterns àuncontrolled proliferation.
o Damage to regulatory genes:
§ Results in loss / gain of function of:
• DNA repair Genes
• Cell Ageing Genes
• Protooncogenes
• Growth-inhibiting (anticancer) Genes
• Apoptosis Genes
• Clonal expansion: cancers arise from a single cell with uncontrolled proliferation.
>
DUPLICACIONES
Defects in DNA Repair Genes:
• Genetic mutations happen all the time.
• However, DNA is repaired by the cell.
• Defective DNA repair can lead to uncorrected mutations à cancer
Defects in Cell Ageing Genes:
• Cellular age is determined by the number of divisions.
• When cells age, they enter senescence: a terminal non-dividing state.
• Mutations that enable the cell to avoid senescence à cancer.
www.MedStudentNotes.com
Cancer, Cell Death & Cellular Ageing
Growth Characteristics of Normal Cells:
• Subject to contact inhibition
• Limited lifespan esperanza de vida
→
• Anchorage dependant
• Growth-factor dependant
• Able to apoptose.
Growth Characteristics of Tumour & Cancer Cells:
• Not subject to contact inhibition
• Unlimited lifespan
• Anxhorage Independant
• Unresponsive to growth-inhibitors
• Unable to apoptose.
• Differentiate independently.
o Differentiated tumours = teratomas.
o May form teeth, hair, bone, nails, toes, brain matter etc.
General Characteristics of BENIGN TUMOUR CELLS:
• Lower mitotic index than cancerous tissue.
• Well-defined capsule
• NOT INVASIVE
• Well differentiated – still exhibit characteristics of their normal cells of origin.
• NOT METASTATIC
General Characteristics of METASTATIC CANCERS:
• Abnormally high mitotic rate
• Show signs of de-differentiation
o have features of primordial stem-cells
• Disordered growth patterns
o Grow as a chaotic mass in all directions
• Can be Metastatic (Colonise distant tissues)
o Cells can break away from primary
tumour & travel through blood/lymph.
o Establish new tumours (secondaries)
called metastases.
• Show gross genetic abnormalities.
o Aberration in chromosome number
o Deletions, translocations in genome
• Grow in the absence of growth factors.
• Are Immortal
o Escape cellular ageing (senescence)
o Many also don’t apoptose
• Malignant phenotype is heritable.
o Cancer cells propagate through many
mitotic divisions without losing cancerous features.
www.MedStudentNotes.com
, Cause of Cancer
• Genetic mutations that are non-lethal to the cell.
• Results from mutagens:
o Chemicals
o Radiation
o Carcinogens
o Free-Radicals
o Microbes (viruses)
o Inherited.
• DNA damage = dysregulated growth patterns àuncontrolled proliferation.
o Damage to regulatory genes:
§ Results in loss / gain of function of:
• DNA repair Genes
• Cell Ageing Genes
• Protooncogenes
• Growth-inhibiting (anticancer) Genes
• Apoptosis Genes
• Clonal expansion: cancers arise from a single cell with uncontrolled proliferation.
>
DUPLICACIONES
Defects in DNA Repair Genes:
• Genetic mutations happen all the time.
• However, DNA is repaired by the cell.
• Defective DNA repair can lead to uncorrected mutations à cancer
Defects in Cell Ageing Genes:
• Cellular age is determined by the number of divisions.
• When cells age, they enter senescence: a terminal non-dividing state.
• Mutations that enable the cell to avoid senescence à cancer.
www.MedStudentNotes.com
