126. MECOM rearrangement by Pericentric Inversion 3 presents a diagnostic challenge

Aly Abdelkareem

Zhenya Tang

I am currently an Associate Professor at Department of Hematopathology, the University of Texas MD Anderson Cancer Center (UTMDACC) in Houston, TX. My research interests include but are not limited to genomic aberrations in hematologic malignancies, lung cancer and other solid tumors.

I have attended and obtained my MD and MS degrees from Tongji Medical University (now Tongji Medical College, Huazhong University of Science and Technology), China and PhD degree from Albert-Ludwigs University of Freiburg, Germany. I have received his fellowship trainings in Clinical Cytogenetics and Clinical Molecular Genetics at the Institute of Genomic Medicine, New Jersey Medical School/Rutgers University in Newark, NJ. I am certified by the American Board of Medical Genetics and Genomics (ABMGG). In addition to my clinical services, I am also interested in translational research, mainly on biomarkers which are being applied and/or potentially applicable to diagnosis and clinical management of patients with hematologic malignancy, lung cancer and other solid tumor. More information about my research interests can be found through this link: https://faculty.mdanderson.org/profiles/zhenya_tang.html

Abstract

Zhenya Tang, Wei Wang, Gokce Toruner, Su Yang, Hong Fang, Jie Xu, Beenu Thakral, Ming Zhao, Edward Ayoub, Ghayas Issa, C. Cameron Yin, M. James You, Joseph Khoury, L. Jeffrey Medeiros, Guilin Tang

The University of Texas MD Anderson Cancer Center, Houston, TX, USA

MECOM rearrangement derived from classic inv(3)(q21q26.2)/t(3;3)(q21;q26.2) and other 3q26.2 abnormalities is often associated with myeloid neoplasms and affected patients have rapid disease progression and a poorer prognosis. However, some 3q26.2 abnormalities can be subtle or cryptic and consequently overlooked by conventional karyotyping. In this study, we report 14 patients with myeloid neoplasms with a pericentric inv(3)/MECOM rearrangement, including inv(3)(p23q26.2)( n=9); inv(3)(p25q26.2)(n=4) and inv(3)(p13q26.2)(n=1). The myeloid neoplasms were classified as acute myeloid leukemia (n=12) or myelodysplastic syndrome (n=2). The cytogenetic abnormalities were initially missed at referral hospitals and by our technologists in 13 (93%) cases. Monosomy 7 and/or r(7) were detected by referral hospitals and/or our laboratory in 10 (71%) cases which triggered the MECOM FISH tests and final determination of pericentric inv(3) due to the break-apart MECOM FISH signals locating on 3p and 3q simultaneously in at least 7 cases (50%). With a median clinical follow-up of 5 months (range, 0-17 months) after the detection of pericentric inv(3), 10 patients died, 3 had persistent disease (refractory or partial response to chemotherapy), and 1 was alive in complete remission after hematopoietic stem cell transplant. In summary, pericentric inv(3)/MECOM rearrangement can be easily overlooked by conventional karyotyping. The MECOM FISH test plays a decisive role in recognition of this type of 3q26.2 abnormality. New potential markers than -7 and r(7) leading to further testing and recognition of pericentric inv(3) are necessary.