Human B-lymphocyte precursors do not express the N-myc gene

Area of Science:

• Oncology
• Molecular Biology
• Developmental Biology

Background:

• N-myc oncogene expression is linked to neuroblastoma, retinoblastoma, and small cell lung carcinoma.
• Increased N-myc expression and gene amplification in neuroblastoma correlate with disease stage and prognosis.
• N-myc is expressed in early murine development but lost in later stages, and present in Abelson murine leukemia virus-transformed pre-B cells.

Purpose of the Study:

• To investigate whether human B-lymphocyte precursors exhibit increased N-myc expression.
• To determine if N-myc expression in human neoplastic B cells correlates with developmental stage or prognostic group.

Main Methods:

• DNA and RNA extraction from human B-cell lines representing various developmental stages (null, pre-pre-B, pre-B, mature B).
• Southern and Northern blot analysis using the N-myc probe (pNB-1).
• Immunocytochemical studies for N-myc nuclear protein detection; neuroblastoma cells as positive controls.

Main Results:

• N-myc expression was detected in positive control neuroblastoma cells.
• No N-myc expression was found in any of the tested mature human B cells or human B-lymphocyte precursor cells.
• Immunocytochemistry also failed to detect N-myc nuclear protein in human B-lymphocyte precursors.

Conclusions:

• Human pre-B cells do not express increased levels of N-myc RNA, contrasting with murine B-cell precursors.
• N-myc oncogene expression in human neoplastic B cells does not appear to correlate with developmental stage or prognostic group.