Help the development of the site, sharing the article with friends!

Pathomorphological examination in the case of lung cancer is to accurately determine the histological type and to demonstrate or exclude important - from the practical point of view - genetic disorders. It is necessary to choose the right treatment for a given type of lung cancer.

The task of the pathologist who carries out thepathomorphological examinationisto identify the type of lung cancerand to determine its type and histological subtype as precisely as possible.

The next step is to assess the genetic profile of the collected neoplastic tissue, which in practice means finding or excluding the presence of a given genetic disorder for which a dedicated treatment has been developed.

Pathomorphological examination in lung cancer: methods

The methods directly assessing the genetic material are used for this purpose:

  • fluorescent In situ hybridization (FISH) method
  • polymerase chain reaction (PCR) method
  • immunohistochemical (IHC) method, which determines the presence or absence of an abnormal protein resulting from a given genetic disorder (indirect assessment of the disorder occurrence).

There is no one common diagnostic method suitable for all types of genetic disorders, therefore the process is extremely complex and depends on the locally available technical and organizational capabilities.

Lung cancer: diagnosis of the histological type

- Due to the development of knowledge and the introduction of drugs used in targeted therapy, the pathomorphological diagnosis of lung cancer has changed significantly. For many years, the requirement was to diagnose cancer and differentiate between small cell carcinoma and other histological types (non-small cell) - says Prof. Włodzimierz Olszewski, consultant in the field of cancer pathology in CO-I.

- Currently, it is required to accurately determine the histological type and to demonstrate or exclude important - from the practical point of view - genetic disorders. It is necessary to choose the right treatment - adds prof. Włodzimierz Olszewski.

Lung cancer: many genes to check

The pathologist's task is - in the case of lung cancer - to secure and select representative material for molecular tests.

As a result of thesetests, it is known whether there is a mutation in the EGFR gene, which qualifies the patient to use one of the targeted drugs.

These tumors also contain mutations of the K-RAS gene, the presence of which is a contraindication to such treatment (in clinical practice, testing these mutations in lung cancer is not advisable, because EGFR and K-RAS mutations are mutually exclusive).

In the phase of introducing to clinical practice, the presence of the EML4-ALK fusion gene is being assessed.

This gene is found in tumors that are EGFR-negative and K-RAS-negative, therefore the determination of the possible presence of this gene is performed in cases where no mutation of the EGFR gene has been found.

In conclusion, the recommended algorithm of the diagnostic procedure should firstly consist in assessing the presence of the EGFR mutation and in patients who do not find it, testing for ALK rearrangement.

Pathomorphological examination: what tissue material?

Tissue material suitable for evaluation of this mutation may be a tissue piece containing the appropriate percentage of neoplastic tissue (more than 30 percent) or cytological material, especially fine needle aspirate.

It is important to emphasize that a detailed histological assessment, as well as the above-mentioned molecular biology tests, are performed on material collected for routine pathomorphological diagnostics.

However, due to the limited amount of this material, in cases of advanced lung cancers (small bronchial specimens or cytological material) it is necessary to use a strict diagnostic algorithm.

Such tests should be performed in reference pathomorphology laboratories closely cooperating with molecular diagnostics laboratories.

Press materials

Help the development of the site, sharing the article with friends!

Category:

Oncology