Molecular classification of soft tissue sarcomas for adequate diagnosis: A study on the northeast population of Morocco

Rhizlane El Koubaiti; Asmae Mazti; Mustapha Maaroufi; Mohammed El Idrissi; Abdelhalim El Ibrahimi; Abdelmajid El Mrini; Touria Bouhafa; Samira El Fakir; Karim Ouldim; Samia Arifi; Laila Chbani

doi:10.1016/j.heliyon.2022.e10673

Molecular classification of soft tissue sarcomas for adequate diagnosis: A study on the northeast population of Morocco

Heliyon. 2022 Sep 17;8(9):e10673. doi: 10.1016/j.heliyon.2022.e10673. eCollection 2022 Sep.

Authors

Affiliations

¹ Biomedical and Translational Research Laboratory, Faculty of Medicine and Pharmacy, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
² Pathology Department. Hassan II University Hospital, Faculty of Medicine and Pharmacy Fez, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
³ Department of Radiology, Hassan II University Hospital, Faculty of Medicine and Pharmacy Fez, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
⁴ Department of Trauma-orthopedics B4, Hassan II University Hospital, Faculty of Medicine and Pharmacy Fez, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
⁵ Department of Radiotherapy, Hassan II University Hospital, Faculty of Medicine and Pharmacy Fez, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
⁶ Department of Epidemiology and Public Health, Hassan II University Hospital, Faculty of Medicine and Pharmacy Fez, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
⁷ Laboratory of Medical Genetics and Oncogenetics, HASSAN II University Hospital, Fez, Morocco.
⁸ Medical Oncology Department, Faculty of Medicine and Pharmacy Fez, Sidi Mohamed Ben Abdellah University, Fez, Morocco.

Abstract

Background: Soft tissue sarcomas (STS) are a heterogeneous group of tumors. For adequate therapeutic management, an accurate diagnosis is necessary. In Morocco, the diagnosis is essentially based on the morphological and immunohistochemical study. Compared to other techniques, fluorescence in situ hybridization (FISH) is easier to develop and less expensive. This study aims to assess the feasibility and utility of implementing FISH technique to improve diagnostic accuracy and establish a good classification.

Material and methods: This is a retrospective cohort study. 211 cases of mesenchymal tumors were included. Hematoxylin Eosin Safran (HES) staining was performed in all cases followed by immunohistochemistry (IHC). FISH was performed in all cases with suspected STS. The probes used were EWSR1, MDM2 and SS18. The performance of FISH and histopathological test were evaluated by the ROC curve method (receiver operating characteristic). We evaluated the concordance between FISH and real time PCR by Cohen test.

Results: The real-time PCR technique showed good agreement with the FISH test by a Kappa coefficient of 60% (p = 0.035). FISH was able to confirm that it is more accurate (Youden's Index = 91%) than histological/immunohistochemical analysis (Youden's Index = 51%), as well as the positive predictive value was higher (100%) with an ROC curve finding a larger area under the curve of 0.953 (95% CI: 0.918-0.988), p = 0.000 which supports that FISH shows high performance to present an accurate final diagnosis.

Conclusion: This is the first and the largest Moroccan series for the molecular diagnosis of STS by FISH. Our study shows that paraffin FISH is a sensitive and specific ancillary tool in the diagnosis of STS when used in the appropriate clinicopathological context.

Keywords: Diagnosis; Fluorescence in situ Hybridization; Molecular classification; Soft tissue sarcomas.