Carcinogenesis , invasion & metastasis


Published on

Carcinogenesis , invasion & metastasis pathology medicine
medical pathology
cancer initiation

Published in: Technology, Health & Medicine
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Carcinogenesis , invasion & metastasis

  1. 1. Carcinogenesis , Invasion & Metastasis Kanishka de Silva MS FRCS Consultant Oncological Surgeon Teaching Hospital Kandy
  2. 2. • Even in the absence of the original stimulus which provoked it • Invades the surroundings and metastasise regionally & distally becoming a systemic disease. What is Malignancy ( Cancer) ? Monoclonal cell line that : - grows independently - uncontrollably - in an uncoordinated manner - at the expense of the normal tissues.
  3. 3. Carcinogenesis Process of conversion of normal cells into malignant cells . Result of a disturbance in : - control of cell proliferation - cell differentiation - relationship of cells to each other and to their surrounding
  4. 4. • Cells of the body : differentiated cells & stem cells • Cancer occur in : stem cells (rather than dedifferentiated mature cells) • Cancer treatment : must be aimed at eradication of malignant stem cells. Normal stem cells replace the ageing cell Malignant stem cells undifferentiated cell mass. Cells with carcinogenic potential
  5. 5. Proto-oncogene (Accelerator) Gene products Cell division, GF , GFR, 2nd Mes Prot, Differentiation DNA binding proteins Ageing & Death Tumour Sup. gene ( Breaks ) Genetic basis of carcinogenesis
  6. 6. Carcinogens Proto-oncogene Over expression , Point mutation Oncogene Fusion Tumour suppressor Mutation , Deletion Lost
  7. 7. Anti-cancer mechanisms of our body DNA repair mechanisms -------------- bio-engineers Immune system ------------------------- police • Multiple cancers could occur in rare, autosomal recessively inherited diseases where there is an inability to repair damaged DNA (Xeroderma pigmentosum, Bloom’s syndrome, ataxia telangiectasia etc. ), & immune deficiency states (inherited and acquired).
  8. 8. Mechanism of Invasion and Metastasis Invasion and metastasis is a multi-stepped process : • Angiogenesis - Tumour acquires an additional blood supply • Homotypic cell adhesion lost - Normal cell adhesion is due to desmosomes, negative cell surface charge and calcium dependent adhesion molecules – cadherins. • Adhesion of tumour cells to the BM & extracellular matrices – Mediated by a receptor-ligand mechanism known as laminin & integrin. • Proteolysis - Cells penetrate through the basement membrane and extracellular matrix • Cells move through the connective tissue matrix and invade natural anatomic pathways of spread such as lymphatics, blood vessels and serosa- lined cavities.
  9. 9. Sites of high metastatic predilection • Liver • Lungs • Bones
  10. 10. Asymptomatic symbiotic cancer carriers Many cancers and pre-malignant forms go unnoticed for many years : - 10-20% of normal men over 45 years have latent prostate cancers - Screen detected malignancies may not surface for years - Breast cancer deposits may occur even 20 - 30 yrs after treatment. Therefore it is apparent that many people may be unaffected by overt cancers throughout their lifetime, all the time having subclinical disease which was never detected. Thus it could be said that these people were in an asymptomatic symbiosis with their cancers.
  11. 11. Cancer as a chronic ailment • Better to consider cancer as a chronic illness rather than a death warrant as there may be quite a number of asymptomatic symbiotic cancer carriers in our society. • This concept would help to shed some stigma attached with cancers as the sufferer would now be considered as a person with a chronic life long disease rather than a necessarily fatal illness.
  12. 12. Do we need a cure ? What is our goal ? • In cancer treatment, thus cure constitutes a questionable entity. • What is important is quality of life. • If this has been achieved whether we have obtained a cure or an asymptomatic symbiosis may not matter as far as that person is concerned.
  13. 13. Thank You