Cytogenetic
Investigation of Laser-Capture Microdissected Carcinoma In
Situ Cells from Testicular Tissue
Department of Growth and Reproduction, GR-5064, Juliane
Marie Centre, University
(ANNEMARIERH06096OTTESEN@rh.dk)
A series of cytogenetic
investigations of overt testicular germ cell tumours, seminomas and
nonseminomas previously revealed a characteristic pattern of chromosomal
imbalances. However there were only few studies of carcinoma in situ (CIS), the
precursor cell of testicular germ cell tumours of adolescents and young adults.
This mainly was due to technical problems caused by a low number of CIS cells
located within the testicular tubules surrounded by several other types of germ
cells as well as somatic cells. To overcome this problem, we laser-capture
microdissected CIS cells from nine cases of CIS, either from tissue without any
invasive tumour or from testicular parenchyma adjacent to overt tumours. Prior
to detection of cytogenetic abnormalities by high-resolution comparative
genomic hybridisation (HR-CGH) analysis, DNA was amplified by degenerate
oligonucleotide primed PCR (DOP-PCR) and directly labelled with a mixture of
FITC-dUTP and FITC-dCTP. HR-CGH analysis revealed extra chromosome arm 12p
material in six out of seven cases with CIS adjacent to overt tumours. These
cytogenetical data indicated that extra 12p material is not present in the dormant CIS cell prior to development of an invasive tumour.
Thus the gain of extra chromosome 12 material is most
likely associated with a more malignant progression of the CIS cell and may not
be an early event in the neoplastic transformation. In addition, this study
confirmed that laser-capture microdissection followed by DOP-PCR of purified
DNA provides good quality material suitable for CGH analysis even in low
numbers of scattered cells.