Differential expression of alternatively spliced c-erbB-2 mRNA in primary tumors, lymph node metastases, and bone marrow micrometastases from breast cancer patients.
We established an RT-PCR method to measure the amount of a 2.3-kb alternatively spliced mRNA of the human c-erbB-2/HER-2 proto-oncogene relative to the 4.6-kb full-length transcript. For the first time, we demonstrated production of c-erbB-2 extracellular domains via alternative splicing in breast cancer tissues, lymph node and bone marrow micrometastases. In 15 c-erbB-2-positive primary breast tumor samples, we found two significantly distinct subgroups: 6/15 had a low level of the extracellular fragment, and 9/15 showed an average 4.4-fold higher amount of the alternatively spliced mRNA. Additionally, six lymph nodes and six bone marrow aspirates from metastatic breast cancer patients were analyzed: 5/6 lymph nodes and 6/6 bone marrow aspirates were found to produce elevated relative amounts of the truncated fragment. The results demonstrate that our method is suitable for sensitive detection of c-erbB-2-positive micrometastasis and strongly suggest that the alternatively spliced c-erbB-2 variant is involved in the development of micrometastasis in breast cancer.
Gebhardt
F
F
Institut für Klinische Chemie und Laboratoriumsmedizin, Universität Münster, Münster, 48129, Germany.
Zänker
K S
KS
Brandt
B
B
D017398:Alternative Splicing; D001483:Base Sequence; D019046:Bone Marrow Neoplasms / Q000235:genetics / Q000378:metabolism / Q000556:secondary; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D005260:Female; D015870:Gene Expression; D018734:Genes, erbB-2; D006801:Humans; D008207:Lymphatic Metastasis / Q000235:genetics / Q000503:physiopathology; D010446:Peptide Fragments / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D016133:Polymerase Chain Reaction; D000090063:Proto-Oncogene Mas; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D012334:RNA, Neoplasm / Q000235:genetics* / Q000378:metabolism*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics
D017931:DNA Primers; D010446:Peptide Fragments; D000090063:Proto-Oncogene Mas; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D018719:Erb-b2 Receptor Tyrosine Kinases; C000715470:MAS1 protein, human