week 4 lecture 1: neoplasia 1

• In developed countries, cancer is the second-leading cause of death
• how many people will die of cancer in the UK, over the next year?

  100,000
• where is colorectal cancer more common?

  in countries whose inhabitants eat a more refined diet
• low-incidence countries may conceal high-incidence regions
• give an example of an instance where a low-incidence country conceals a high incidence region

  oesophageal carcinoma is relatively common among black people in the USA
• smoking at the rate of 10 cigarettes per day increases the risk of developing lung cancer tenfold
• how can neoplasia be defined?

  as a set of disorders showing a disturbance in:

  • cell proliferation
  • cell differentiation
  • the relationship between cells and the surrounding stroma
• what is differentiation?


  the sum of processes by which cells in a developing multicellular organism achieve their specific set of functional and morphological characteristics
• what does differentiation usually involve?

  a progressive restriction of genomic expression
• impairment of differentiation is common in neoplasia
• generally, how is cancer behaviour and prognosis affected by poor differentiation within an organism?

  the behaviour of cancers is worse, and the prognosis is poorer
• changes in differentiation do not necessarily mean that neoplastic transformation has occurred
• what is metaplasia?

  the (often abnormal) transformation of one differentiated type of tissue into another type of tissue
• what are the 3 most common cancer types across the world?

  1. breast
  2. prostate
  3. lung
• what is epidemiology?

  the study of the determinants, occurrence, and distribution of health and disease in a defined population
• which kind of cancer is more common in men than women?

  lung
• which kind of cancer is more common in women than men?

  thyroid
• which kind of countries is colorectal cancer more common in?

  countries whose inhabitants eat more refined (processed) diets
• defined a processed diet

  removed nutrients/fibre
• when/where does metaplasia occur frequently?

  in chronically irritated cells, or cells in a hormonal environment
• what are changes in differentiation affected by?

  the interaction of cells within their microenvironment, and between adjacent cells
• what is an example of cells within a microenvironment?

  mesenchymal and epithelial elements
• what feature must cells (from which a neoplasm) arises have?

  they must be able to be stimulated to divide (including stem cells)
• what features must two daughter cells of a stem cell have, after the stem cell's division?

  one daughter cell must retain the ability to divide, whereas the other should retain the ability to differentiate
• what are the two kinds of neoplasm?

  1. benign
  2. malignant
• what does the term 'non-neoplastic proliferation' mean?

  the abnormal growth of cells that is not caused by a tumor/cancer
• what are the 5 main examples of non-neoplastic proliferative conditions?

  1. hypertrophy
  2. hyperplasia
  3. metaplasia
  4. dysplasia
  5. inflammation-related proliferations
• what is hypertrophy?

  increase in cell size (not number)
• what is hyperplasia?

  increase in cell number

  -> this can lead to hypertrophy
• what is metaplasia?

  a reversible change in cell populations from one fully differentiated form to another fully differentiated form
• what is dysplasia?

  abnormalities which are characteristic of neoplasia, but WITHOUT the invasion of surrounding tissues
• what are inflammation-related proliferations caused by?

  chronic inflammation as part of the healing response
• what does hypertrophy occur in response to?

  physiological stimuli or pathological conditions
• give an example of a physiological stimulus that could cause hypertrophy

  muscle hypertrophy can be caused by exercise
• give an example of a pathological condition that can cause hypertrophy

  cardiac hypertrophy can be caused by hypertension
• what does hyperplasia occur in response to?

  physiological stimuli or pathological conditions
• give an example of a physiological stimulus that can cause hyperplasia

  hyperplasia can occur as a normal response to stimuli, such as breast cancer during pregnancy
• give an example of a pathological condition causing hyperplasia

  hyperplasia occurs as an abnormal stimuli, such as hormone imbalances causing endometrial hyperplasia
• give an example of metaplasia

  respiratory epithelium in the bronchi transform into stratified squamous epithelium, in response to smoking
• give an example of an inflammation-related proliferation

  hyperplasia of gastric mucosa, caused by chronic gastritis