It has long been a well-known fact that cancer is characterised by uncontrolled cell growth. Depending on where the abnormal cell behaviour is localised, a distinction is made between liver cancer, lung cancer, breast cancer, etc.

However, the tumours of patients with identical diagnoses differ from each other. Indeed, the molecular level of cancer characterisation allows for narrower and more clinically important categories to be distinguished. At the same time, a more detailed classification requires the necessary number of patients in a particular group to formulate an effective therapeutic plan. And subjects in several large groups may provide more general information, making it much more difficult to prescribe an accurate and successful therapy in each clinical case.

Scientists are reviewing the classification of T-cell lymphoma, a malignancy of the immune system, given the molecular characteristics of the tumour. The choice of tumour is determined by its lack of study, the rarity of the disease and the high number of deaths of patients with this diagnosis.

The World Health Organisation lists more than 30 subtypes of T-cell lymphoma. Thus, it is a diverse and heterogeneous group, which makes it difficult to characterise. After all, appropriate diagnostic capabilities are needed to distinguish all subtypes of a given tumour. For example, some subtypes manifest themselves more aggressively than others, so it is important to identify and investigate them for a better understanding of the individual treatment process.

By targeting a particular subtype of lymphoma – anaplastic large-cell lymphoma with a negative chromosomal gene rearrangement – scientists have studied it at the genetic level. The results showed a limited system for classifying the tumour. To date, the researchers have identified several subclasses within this lymphoma, two of which result from chromosomal rearrangements in two genes (DUSP22, TP63).

Patients with DUSP22 chromosomal rearrangement are clinically well, which is associated with a less aggressive tumour. This nature of the tumour allows its genome to be studied without changing the underlying DNA sequence. Scientists also note changes in DNA methylation, which affects gene expression, which is not characteristic of cancer.

In such a case, the immune system starts attacking the expression, trying to eliminate cancer. Incorrect DNA methylation in such tumours can trigger gene expression and allow the immune system to recognise the tumour. Not only does activation of the immune system makes patients feel better, but it also extends the therapeutic options to enhance the immune response in patients without DUSP22 rearrangement, which makes tumour recognition more difficult.

Based on research results, the International Consensus Classification of lymphomas has recognised the DUSP22 chromosomal rearrangement as defining the genetic subtype of anaplastic large-cell lymphoma. Also, this subtype of lymphoma with the DUSP22 rearrangement has been recommended by the National Comprehensive Cancer Network as one that does not require mandatory intensive therapy.