What is EHE?
Haemangioendothelioma (HE) is the name for a group of very rare vascular cancers involving cells that line the inside of blood vessels (endothelial cells). Vascular cancers account for only a fraction of 1% of all cancers. ‘Epithelioid’ refers to the elongated shape of the cells when seen under the microscope. Tumours can involve liver, lung, bone, lymph node, skin and other soft tissues, and they can occur simultaneously at multiple sites. EHE occurs in people of either sex and of any age.
What causes EHE?
EHE is caused by a specific chromosomal rearrangement or translocation (swapping of genetic material) called the ‘WC Fusion’. This discovery was made by dedicated scientists studying the molecular biology of EHE. The translocation, between chromosomes 1 and 3, was identified in the tumour cells of ~90% of EHE patients. But it was not present in people not suffering from EHE, nor in other types of vascular tumour. The translocation creates a new ‘fusion gene’, which in turn generates a new fusion protein that is highly likely to be responsible for the abnormal endothelial growth seen in EHE. The WC Fusion is specific to EHE and as a result can be considered ‘disease-defining’ for EHE.
What is the good news?
EHE can be indolent (slow growing) and may be characterised by slow tumour growth and mild symptoms. Some patients have no symptoms for years. Rarely, EHE can even go into spontaneous remission. So, newly diagnosed EHE patients usually have time to learn about the disease, find an expert, get second opinions and decide what to do.
What is the not-so-good news?
EHE tumors can grow rapidly, spread or exhibit destructive behaviour, even after long periods of dormancy. In short, EHE is unpredictable. Therefore, routine surveillance scans are often done as a precaution, to identify indolent tumors that have become aggressive.