Histology, microscopy, anatomy and disease
Histology, microscopy, anatomy and disease

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Histology, microscopy, anatomy and disease

2.3 Immunohistochemistry

As you read in Week 1, the staining of cells and sections with antibodies has revolutionised histology as it allows the identification and localisation of individual molecules.

A molecule that binds to, and is recognised by, an antibody, is called an antigen, and, in the context of histology, such antigens are often referred to as markers, since they act as ways of recognising a particular cell. Many markers are designated by a CD number. Indeed, more than 250 markers have been assigned CD designations.

As you read previously, immunohistochemistry (IHC) is particularly valuable for distinguishing different cell types in the diagnosis of cancer. For example, different classes of lymphocyte appear virtually identical in size and shape (morphology), but they can be distinguished according to their surface markers. All T lymphocytes express CD3, and the two major subpopulations of helper T cells and cytotoxic T cells express CD4 and CD8, respectively. Therefore, a T cell lymphoma can be tracked in different tissues using these markers.

Described image
Figure 5 Immunohistochemistry. Double immunolabelling of an Islet of Langerhans in the pancreas identifies insulin-producing cells (blue) and glucagon-producing cells (brown).

Another use for IHC is in guiding treatment. For example, many breast cancers require oestrogen to divide, but a drug called tamoxifen can bind to the oestrogen receptor on the cancerous cells, blocking this proliferative effect. However, this only applies to some cancers, as others do not have an oestrogen receptor and are therefore not susceptible to tamoxifen therapy.

A researcher or clinician can use IHC to identify whether a breast cancer removed by surgery expresses the oestrogen receptor. The clinician wants to treat the patient so as to prevent any secondary tumours from growing and with this information they can decide whether or not tamoxifen therapy is appropriate.


Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371