The role of variant t(9;22) in Chronic Myeloid Leukemia: A report of 5 cases.

Durak Aras B., Işık S., Günden G., Üsküdar Teke H.

14th European Cytogenomics Conference, Montpellier, Fransa, 1 - 04 Haziran 2023, ss.14

  • Yayın Türü: Bildiri / Özet Bildiri
  • Basıldığı Şehir: Montpellier
  • Basıldığı Ülke: Fransa
  • Sayfa Sayıları: ss.14
  • Eskişehir Osmangazi Üniversitesi Adresli: Evet

Özet

Chronic myeloid leukemia (CML) is a hematological malignancy characterized by the Philadelphia chromosome (Ph). The Ph chromosome is formed as a result of t(9;22) and is detected in 90% of CML patients. However, 15% of the detected Ph chromosomes result from variant t(9;22) (vPh). Variant t(9;22) is grouped as 3-way, 4-way, and 5-way according to the number of chromosomes involved in the translocation in addition to the 9th and 22nd chromosomes.
We detected the vPh chromosome in 5 cases using the conventional cytogenetic method. It was observed that vPH detected in 3 cases had one-step and 3-way mechanisms. The karyotype results detected in the cases are as follows:
Case 1: 46,XY,t(8;9;22)(p21;q34;q11.2)[4]
Case 2: 46,XY,t(1;9;22)(q?;q34;q11)[3]
Case 3: 46,XY,t(9;22;1)(q34;q11;p36.2?)[5]
Case 4: 46,XY,t(9;22)(q34;q11)[3]/46,XY,t(5;9;22;7)(q31;q34;q11;q31)[2]/46,XY[11]
Case 5: 46,XY, t(9;10;22)(q34;q?;q11)[1]46,XY[10]
Although none of the 5 cases we reported had a major molecular response, all were chronic phase CML. In the treatment process, we determined that 3 patients switched from imatinib to nilotinib (cases 1, 3, 5), one patient switched from imatinib to dasatinib (case 2), and the remaining one patient (case 4) continued imatinib treatment.
In the literature, vPh occurring as one-step and 3-way is observed more frequently. In addition, it is generally stated that the variant pH chromosome is not different from the typical t(9;22) clinically and prognostically. However, unresponsiveness to imatinib has been reported in cases. It is noteworthy that our cases also did not respond to imatinib. In addition, the vPH chromosome detected in case 4 has not been reported in the literature before. The patient was treated with imatinib and died at 106 months. As a result, to clarify the prognostic effects of vPH chromosomes, the mechanisms of occurrence of these translocations, and more case report data are needed.