Abstract
A series of 52 primary human bronchial carcinomas was studied karyotypically using G-banded metaphase preparations after short term culture of solid tumour material removed at operation. All the tumours studied exhibited multiple gross chromosomal abnormalities, both numerical and structural. There was a clear indication of non-random involvement of the different chromosomes in these abnormalities, differential participation appearing to be related to chromosome length and particuarly evident for the longer chromosomes. Chromosomes 1,3,5,7, and 8 contributed more to marker chromosomes and to extra chromosomal material, and chromosomes 2,4 and 6 were involved less, than the rest of the chromosomes. Material from chromosome 15 was found to be missing from cells more frequently than that from any of the other chromosomes. In discussion of these results, the value of modal chromosome number as an index of chromosomal abnormality is questioned. The implications of the findings for theories of the significance of chromosomal abnormality in the aetiology and progression of tumours are discussed, with particular emphasis on the stemline concept and on processes of clonal selection in tumours. No significant differences were apparent amongst the results obtained for the different histological groups of carcinomas, or from patients of different ages, or between the two sexes.