Neoplasia, invasion and metastasis
How accumulated mutations release a cell from normal growth controls, how an epithelium passes through dysplasia and carcinoma in situ to invasion through its basement membrane, how cancer spreads, and how tumours affect the whole body.
By the end, you can
- Describe how normal epithelium controls growth, maturation and cell death.
- Explain how mutations in oncogenes, tumour suppressor genes and DNA repair genes accumulate.
- Distinguish dysplasia, carcinoma in situ and invasive carcinoma by the basement membrane.
- Describe the steps of metastasis and the usual routes of spread.
- Distinguish benign from malignant tumours and relate local and systemic effects of cancer to their mechanisms.
- Recognise the gross and microscopic features of malignancy and its spread, name grade and stage as concepts, and explain how surgery, radiotherapy and the main drug classes act on cancer.
What it is
A neoplasm (tumour) is an abnormal mass of tissue whose growth exceeds and is uncoordinated with that of normal tissue and persists after the stimulus that started it. Benign neoplasms stay where they arise; malignant neoplasms (cancers) invade surrounding tissue and can metastasise to distant sites. A carcinoma is a malignant neoplasm of epithelium, the commonest kind of cancer.
3 types to tell apart
- Dysplasia
- Disordered growth and maturation with atypical cells, confined to the epithelium; graded low to high; may regress or progress.
- Carcinoma in situ
- Malignant-looking cells through the full thickness of the epithelium, with the basement membrane still intact: cannot yet spread.
- Invasive carcinoma
- Cells have breached the basement membrane into the connective tissue, where they can reach vessels and spread.
US spelling: tumour → tumor.
Normal function
Controlled growth in a normal epithelium
In stratified squamous epithelium, such as the lining of the cervix, mouth or skin, cells divide only in the basal layer. Their daughters move upwards and mature in order, flattening as they reach the surface, so the has a regular, layered pattern with small, uniform .
The epithelium sits on a , a thin sheet of collagen and other proteins that separates it from the beneath. Blood vessels and lymphatics are in the connective tissue, not the epithelium.
Growth is held in balance by signals that promote division (from growth factors through proto-oncogenes), signals that restrain it (through tumour suppressor genes such as TP53 and RB1), repair of damaged DNA and programmed cell death (apoptosis) for cells beyond repair.
Underlying change · Step 1 of 5
Mutations accumulate in one cell line
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Underlying change · Step 2 of 5
Dysplasia: disordered growth within the epithelium
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 3 of 5
Invasion through the basement membrane
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 4 of 5
Metastasis: spread to distant sites
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Consequences · Step 5 of 5
How tumours affect the body
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Symptoms and signs
Symptoms, signs and findings
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Exam detail
Exam detail
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Treatment
How treatment works
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Recap
Recap
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Self-check
Check your understanding
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .