Korean J Clin Pathol.
1997 Dec;17(6):1157-1175.
Chromosomal Abnormalities and p53 Mutation in Metastatic Hepatoblastoma Cell Line (KPH1)
Abstract
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BACKGROUND: Hepatoblastoma is the most common primary liver tumor in childhood, mostly occurring at the age of 2. Primary culture of the tumor cells (KPH1-P) was performed from the pleural fluid of 17-month-old girl diagnosed as metastatic hepatoblastoma. A new human hepatoblastoma cell line, KPH1 was established after 10th subculture during the subsequent 6 months. Thereafter, tumor cells were ring cloned and 10 clones were named as KPH1-C to KPH1-C10.
METHODS
We investigated for the chromosomal abnormalities in the tumor cells from KPH1-P, KPH1, and KPH1-Cl to KPH1-C10, respectively by cytogenetic analysis. Mutation of p53 gene was analysed by PCR-SSCP and direct sequencing. The status of p53, c-erbB-2, c-myc, K-ras and H-ras gene was also evaluated by Southern blot, along with PCR study for hepatitis B virus infection.
RESULTS
Primary culture cells, KPH1-P revealed a specific chromosomal aberration, such as t(1;12) (q21;q24), +i(1q), i(6p), and +8. The hepatoblastoma cell line, KPH1 and its clones, KPH1-Cl to KPH1-C10, maintained the chromosomal change of +1(1q), i(6p), and +8, but there was a loss of t(1;12) (q21;q24) and a gain of t(7;16) (q21;pter). Southern blot of KPH1 resealed rearrangement of c-mac and c-erbB2. PCR-SSCP and direct sequencing for p53 in KPH1 showed point mutations at exon 8; codon 270, TTT -->CTT; codon 287, GAG --> TAT, codon 290, CGC --> CAA; codon 291, AAG --> AAT, codon 293, GGG --> TAG; codon 297, CAC --> AAC; codon 298; GAG --> AAG. There was a loss of these gone rearrangements and p53 mutation in its clones, KPH1-Cl to KPH1-C10. PCR for hepatitis B virus in KPH1 showed a specific band for the core region of HBV DNA, suggestive of HBV infection.
CONCLUSIONS
In summary a new human hepatoblastoma cell line with 48, XX, +i(1q), i(6p), +8 and t(7;16) (q21;pter) was established. The change of chromosomal aberrations, and the loss of off mutation and rearrangemend of c-myc and c-erbB2 in the process of long term culture is regarded as a secondary change for adaptation to the 'in vitro' cultural environment, rather than a step of cancer progression. The identification of chromosomal break points and related altered genes in the established cell line, KPH1 might provide a useful guideline for studying carcinogenesis and progression of hepatoblastoma in future.