Telomeric length variation in human testicular germ cell tumours

Telomeric length was studied in 5 cases of human testicular germ cell rumours by measuring the length of the terminal restriction fragments (TRFs) containing the (TTAGCG)(n) sequence. Mean TRF length in human placenta used as a source of reference DNA for assessing the effect of cellular ageing was 14 kbp. TRF length in two classical seminomas and a mixed embryonal carcinoma/atypical seminoma ranged from 4 to 14 kbp and from 4 to 23 kbp, respectively, with the same mean value of 9 kbp in both tumour types. In a mixed teratoma/embryonal carcinoma, telomeric length ranged from 14 to 27 kbp with a mean of 20 kbp. In the single case of spermatocytic seminoma studied, telomeric length was up to 100 kbp with a distinct sharp band at similar to 50 kbp, representing the longest, homogeneous telomeres found so far.