Immunohistochemistry - Undifferentiated Flashcards
What are the four main applications of immunocytochemistry
Cell biology - cell cycle, apoptosis, cell differentiation and classificatin
Haematology - leukaemia ID
Immunology - autoimmune disease, immune cell function and distribution
Cell path/ clin cyt - tumour characterisation, microbe detection
Write about autoimmune disease investigation
Identify bound auto-antibodies and immune
complexes – Tissue sample stained by direct
immunofluorescence
* Pernicious anaemia
* Primary biliary cirrhosis
* Skin – bullous blistering disorders
* Kidney - glomerulonephritis
Write about immunostaining in cytology
- Smears, Cytospins
- Fix in alcohol
- Immunostain using polymer-based automated staining
- Develop chromogen [depending on label]
- Counterstain with haematoxylin
How can IHC be used in tumour characterisation
Diagnostic
* Identification of Cell Type
* Histogenicity
Prognostic-
* Biomarkers of grade, growth, genetic aberrations
[oncogenes, Tumour suppressor genes]
Therapeutic
* Biomarkers related to susceptibility to targeted therapy
Write about differentiation
- In biology, describes the processes by which immature cells become mature cells with specific functions.
- In cancer, this describes how much or how little tumour tissue looks like the normal tissue it came from.
- Well-differentiated cancer cells look more like normal cells and tend to grow and spread more slowly than poorly differentiated or undifferentiated cancer cells.
- Differentiation is used in tumour grading systems, which are different
for each type of cancer.
Write about patients with poorly differentiated tumours
Patients with poorly differentiated carcinoma account for
approximately 20% of patients with carcinoma of an unknown
primary site
* an additional 10% of patients have poorly differentiated
adenocarcinoma
Write about tumour heterogeneity
Describes the observation that different tumour cells can show distinct morphological and phenotypic profiles
What six markers make up the markers involved in an undifferentiated tumour panel
Cytokeratin - epithelial tumours
CD45 - Lymphomas - common leucocyte antigen
Vimentin - connective tissue tumours - Sarcoma
S100 - melanomas
Neuron-specific enolase - neural derived tumours
Desmin - muscle cell tumours
Write about tumour subtyping
- Once cell category is identified tumour is subtyped
- Cytokeratin positive – Epithelial cell carcinoma or adenocarcinoma;
could be from many sites - CD45 positive – could be one of 20+ different lymphomas
- Vimentin positive – could be 30+ different tumour types
- Second panel of primary antibodies applied to find out exact cell type
Write about liver tumours
- Liver very rarely has primary tumours
- Tumour sheds cells of to mestasisies -> blood brought to the liver
- Cancerous cells grow in the liver
- Do hep par if primary liver tumour
- If not primary do a CK 7 or CK20
o If both positive its pancreatic
o If CK20 its colon
o If CK7 its breast or ovarian
o If CK19 its pancreatic
What are the subclassifications of adenocarcinoma
Ductal
Lobular
Medullary
Tubular
Mucinous
Papillary
Apocrine
Classify breast adenocarcinomas
Adenocarcinoma in situ
Invasive adenocarcinoma
Write about immunohistochemistry of skin
Viral antigen detection
- Herpes simplex I or II
- Human herpes virus B
Tumour typing = cell typing by antigen expression
What are the 5 tumour classes
- 1.Melanocyte/Melanoma markers -
HMB45, S100, Melan-A,Tyrosinase - Epithelial cell tumours – Cytokeratins [AE1/AE3 or MNF]
- Langerhans cells – CD1a
- Merkel cells – Neuron Specific Enolase, Cytokeratin 20
- 5.Lymphomas, CD45, CD3 – T cell lymphoma
Write about melanoma
Skin, Eye, Acral <400 cases p.a
* Legs - female, Trunk - male
Mostly due to sun exposure
* Sunbeds also associated with raised risk
Commonly from pre-existing moles
Removal by excision – sample for histology
* Cytology – FNA of organs invaded by melanoma cells
Various types:
* Superficial spreading, Nodular, Amelanotic
* Vascular spread to brain, lungs, LN
Write about melanoma investigation
H+E, Immunostaining, Molecular analysis
Antibodies used in melanoma immunostaining: S100, HMB45, Tyrosinase,
MelanA
Classify lymphoma
Hodgkins lymphom
Non Hodgkins lymphoma
Write aboubt hodkgins lymphoma
Reed sternberg cells
Write about Non-Hodgkins lymphoma
- Classification based on cell type, location, phenotype
B-lymphocyte
T-lymphocyte
Low grade / High grade
Specific type – depending on location and cell type:
* Follicular, Mantle cell, Anaplastic
* Nodal, Extra-nodal, Cutaneous, Enteropathy-associated
Write about immunohistochemistry of CD45
Hodgkins lymphoma – Reed Sternberg cells
* CD15, CD30
Non-Hodgkins lymphomas
* T lymphocyte lymphoma
* CD3, CD45RO
B-lymphocyte lymphoma
* CD20, CD79a
Write about Hodgkin’s lymphoma
~1% of all malignancies in Western world
Bimodal age incidence
* First peak at 20-30 years
* Second peak over 50 years
Lymphadenopathy affects cervical (neck) nodes in 60% of cases
~145 cases in Ireland p.a, 60% in under 50s
Write about Reed-Sternberg cells
- Hodgkin’s cells -Large mononuclear cells with prominent
nucleolus and abundant cytoplasm, - Reed-Sternberg cells - Bi-lobed nucleus (mirror image) or multi-lobed nuclei with prominent nucleoli [20-50μm]
Background cell population dependent on subtype
- Mixed cellularit - eosinophils, plasma cells
- Nodular sclerosing - collagen bands
Write about the diagnosis of Hodgkin’s lymphoma
- Morphology – RS, Hodgkins cells
- Immunophenotype – CD15, CD30 positive
- Also IHC + - MUM1, PAX5 proteins
- 50% have EBV in RS cells
- Staging – dependant on how many lymph nodes position and
regions of body affected - Treatment – Radiation, Chemotherapy and/or stem cell
transplantation - Survival – >84% 5 year survival
Write about non-Hodkins Lymphoma
- 2-3% of all malignancies in developed countries
- Wide Spectrum of neoplasms
- Often have widespread disease on presentation
- Vary from indolent to aggressive tumours
- Low-grade or high-grade
- May arise in Lymph nodes or lymphoid tissue
throughout body (GIT, Skin, Brain etc.)
Write about lymphoma immunophenotyping
- CD45 – most lymphomas are positive
- CD15 and CD30 - Hodgkins lymphomas
- CD20+, CD79a+ - B lymphocyte NHL
- CD3+, CD43+ – T lymphocyte NHL
- CD30 – Hodgkins and Anaplastic Large Cell NHL
- Specific markers – each lymphoma has its own
diagnostic profile
Write about lymphadenopathy
- Tumours commonly spread to adjacent lymphatics
- Lymph Node status is a key indicator of prognosis and survival for cancer
sufferers - First line investigation may be FNA cytology
- Accuracy of FNA in metastatic disease is high
- Lymphadenopathy can be first indication of a malignancy
Write about sentinel lymph nodes
- Sentinel – standing, watching
- Sentinel LN - most important LN – node adjacent/closest to
malignant tumour - Highly indicative of stage or spread of the cancer
Write about breast cancer - axillary lymph nodes
If sentinel node is positive for breast cancer , may have axillary nodes
removed or more aggressive therapy
Write about metastatic deposits in lymph nodes
- Local or distant spread
- Identification of primary on morphology and
immunocytochemistry - Any cell types other than lymphocytes in LN indicates
metastatic disease - Micrometastases – small clusters or single cells
Write about common metastatic tumours found in LN
Squamous cell carcinoma
* Lung – mediastinal lymph nodes
Adenocarcinoma
* Breast
* Lung
* Gastric / GI tract
* Ovarian
* Prostate
Melanoma
Write about soft tissue tumours
Subtyping, Vimentin positive
- Desmin – muscle tumours
- Smooth muscle actin – smooth muscle tumours
- CD31 – Endothelial tumours
- CD99 – Ewings sarcoma
Write about Ewings Sarcoma
- a primary malignant small round cell tumour of bone and soft tissue
