Detection of BCR‑ABL1 fusion gene transcripts in the saliva of Nigerian patients with chronic myeloid leukemia

Abstract

Background: The presence of BCR‑ABL1 fusion gene resulting from a t(9; 22) reciprocal chromosome translocation is the molecular hallmark of chronic myeloid leukemia (CML). In the diagnosis and treatment of CML, peripheral blood or bone marrow samples are usually taken for analysis. However, both methods are invasive sample collection methods, thus a noninvasive saliva sample method for the detection of the fusion gene transcripts (BCR‑ABL) was investigated in some Nigerians with CML.

Materials and Methods: Real‑time (RT)‑polymerase chain reaction (PCR) analysis was used to detect BCR‑ABL1 fusion gene in the saliva and blood of 42 Nigerian CML patients. RNA was extracted using RNeasy kit and reverse transcribed by random hexamer priming using murine Moloney reverse transcriptase. BCR‑ABL1 transcript types were first detected by multiplex PCR and then quantified by a duplex RT‑PCR‑TaqMan chemistry with MGB probe and Black Hole Quencher.

Results: Of the 42 subjects, transcript types were detected in 36 (85.7%) samples, e13a2 fusion transcript sub‑type was detected in 9 (21.4%), whereas e14a2 subtype was found in 27 (67.3%); six (14.3%) of the samples did not reveal any of the fusion transcript subtypes. The median BCR‑ABL1 messenger RNA values were 9.38 × 102 in saliva and 10.29 × 104 in blood (P < 0.05). Similarly, the median ABL1 value in saliva (3.11 × 103) was significantly lower (P < 0.01) than in blood (4.22 × 103). However, the median BCR‑ABL1 ratio in saliva (14.5%) was not significantly different (P = 0.8) from that of blood (12.0%).

Conclusion: Saliva may offer an alternative easy‑to‑collect, readily  available, and noninvasive sample for the diagnosis and treatment of CML.

Keywords: BCR‑ABL1, chronic myeloid leukemia, Nigeria, Philadelphia chromosome, saliva