Human B-lymphocyte precursors do not express the N-myc gene.
N-myc expression has been reported in neuroblastoma, retinoblastoma and small cell lung carcinoma. Increased expression associated with gene amplification in neuroblastoma correlates with disease stage and prognosis. N-myc expression has been observed in diverse murine tissues during early stages of development with loss of expression in later stages. Abelson murine leukemia virus (A-MuLV)-transformed pre-B cells express N-myc, whereas mature B cells do not. To determine whether human B-lymphocyte precursors also have increased N-myc expression, we extracted DNA and RNA from representative cell lines, prepared Southern and Northern blots and examined them with the N-myc probe, pNB-1. RNA from the following B-cell developmental stages were examined. One null, 1 pre-pre-B, 3 pre-B (including pre-B-lymphoblastic leukemia, a poor prognostic category) and 5 mature B. Neuroblastoma cells and tissues served as positive controls; negative controls included human muscle, placenta, epithelial cell lines, monocytic, promyelocytic, and T-cell lines. N-myc expression was detected in neuroblastoma cells, but in none of the mature human B or B-lymphocyte precursor cells. Additional immunocytochemical studies performed for N-myc nuclear protein likewise failed to detect this gene product. We conclude that human pre-B cells, unlike murine B-cell precursors, do not express increased levels of N-myc RNA. Expression of this oncogene in human neoplastic B cells does not appear to correlate with developmental stage or prognostic group.
Wetherall
N T
NT
Department of Pathology, Vanderbilt University Medical Center, Nashville, TN 37232-2561.
Vogler
L B
LB
D001402:B-Lymphocytes / Q000378:metabolism*; D004247:DNA / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics; D016259:Genes, myc; D006801:Humans; D007938:Leukemia / Q000473:pathology; D008223:Lymphoma / Q000473:pathology; D009369:Neoplasms / Q000473:pathology; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis* / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D014407:Tumor Cells, Cultured / Q000378:metabolism*
D004273:DNA, Neoplasm; D016271:Proto-Oncogene Proteins c-myc; D012334:RNA, Neoplasm; D004247:DNA