Niels B. Atkin

Diploid-tetraploid relationship among old-world members of the fish family Cyprinidae

Evidence suggesting that the goldfish and the carp of the family Cyprinidae are tetraploid species in relation to other members of the same family were presented. The two barb species, Barbus tetrazona and Barbus jasciatus, were chosen as representatives of diploid members of the family Cyprinidae. These barbs had the diploid chromosome number of 50 and 52 and the DNA value 20–22% that of placental mammals, while the goldfish (Carassius auratus) and the carp (Cyprinus carpio) had the diploid chromosome number of about 104 and the DNA value 50–52% that of placental mammals.

Chromosome 1 aberrations in cancer

Evidence for chromosome #1 involvement in structural rearrangements in cancer is reviewed. There have been adequate studies of cancer at most of the common sites, and at all of these, nonrandom chromosome #1 involvement has been demonstrated. In general, a variety of changes is encountered, irrespective of the site; most commonly, however, the changes result in the duplication of long arm material. It seems that these nonrandom changes, which tend to occur at a relatively late stage, may contribute to the progression of all forms of cancer. However, a small number of chromosome #1 aberrations are also now known, which may represent specific and possibly initiating changes in particular forms of cancer. These include short arm deletions in neuroblastoma and translocations in leukemias and myelodysplasia.

i(12p): specific chromosomal marker in seminoma and malignant teratoma of the testis?

A similar small marker chromosome, frequently present in duplicate, was seen in direct preparations and short-term cultures of each of ten seminomas, one combined seminoma and teratoma, and one malignant teratoma of the testis. In the four most favorable tumors (seminomas) this chromosome was identified as an i(12p). The findings may point to a chromosomal change that is specific for malignant testicular tumors.

Chromosome study of five cancers of the prostate.

SummaryNonrandom chromosome changes were sought in direct preparations of tumour material from the primary site of four carcinomas and one leiomyosarcoma of the prostate. Two of the carcinomas had previously received oestrogen therapy. A deleted chromosome 10, del(10)(q24), was found in all four carcinomas and may represent a specific marker in prostatic carcinoma. Three of the carcinomas also had a deleted chromosome 7, del(7)(q22), while the fourth had a 7p+. Deleted chromosomes 7 and 10 were not identified among the markers present in the leiomyosarcoma. All five tumours contained one or more abnormal chromosomes derived from chromosome 1. A Y chromosome was present in the leiomyosarcoma but in none of the carcinomas.

THE COMPARATIVE DNA CONTENT OF 19 SPECIES OF PLACENTAL MAMMALS, REPTILES, AND BIRDS*

SummaryWith the Deeley integrating microdensitometer incorporating a crushing condenser, the Feulgen stain content of 19 species of placental mammals, birds and reptiles was determined. Arranging the species as a series of pairs, comparative DNA values were obtained which are by and large in good agreement with previous results obtained from two-dimensional measurements of chromosome area.1.Placental mammals as a whole constitute one uniform group with regard to total genetic content. There was no significant difference in DNA values between man, the horse, the dog, the golden hamster and the mouse. The creeping vole with the extremely low diploid chromosome number had a DNA value 10 per cent lower, regarded as a reflection of the loss of centromeric heterochromatin which accompanied a drastic decrease in diploid chromosome number.2.Four representatives of the class Aves also constitute one uniform group with the DNA value 44 to 59 per cent of that of placental mammals.3.The class Reptilia falls into two fairly discrete groups. Six representatives of the order Squamata have a DNA value 60 to 67 per cent of that for placental mammals, while three species representing the order Crocodylia and Chelonia have 80 to 89 per cent.

Break points in chromosome #1 abnormalities of 218 human neoplasms

A survey of 343 break points that lead to chromosome #1 abnormalities in 218 human neoplasms showed that 49.9% were located in or immediately adjacent to the centromeric heterochromatin. Amongst rearrangements with breaks in bands p 12-q21 were 27 isochromosomes, 22 translocations of the long arm, and four translocations of the short arm to the heterochromatic regions of other chromosomes, and 35 deletions resulting in chromosomes consisting mainly or solely of one arm. Deletions following breakage at various sites in the short arm of chromosome #1 are frequent in malignancies and are quite often found in cells that are trisomic for the long arm. It is suggested that fragility of chromosomes generated as a result of early events in carcinogenesis may be one source of chromosome rearrangements, including those of chromosome #1, on which selection can operate and give rise to progressively more malignant clones.

Abnormal chromosomes including small metacentrics in 14 ovarian cancers

In direct preparations of 14 ovarian cancers including 11 primary tumors, chromosomes #1 (12 tumors), #3 (12 tumors, including 3q- chromosomes in five), #6 [eight tumors, including six with a 6q- and two with an i(6p)], #11 (11p + in seven tumors), and #14 (14q+ in at least seven tumors) were most frequently involved in structural aberrations. Also, abnormal small metacentrics were seen in 11 tumors. In ten of these the chromosome appeared to be an i(4p) or i(5p) and in one of these, a mixed Müllerian tumor, there was also an i(12p); the latter anomaly was also present (in duplicate) in a dysgerminoma.

Cytogenetic study of ten carcinomas of the bladder; involvement of chromosomes 1 and 11

In direct preparations of ten untreated transitional cell carcinomas of the bladder, chromosomes #1 and #11 were most frequently involved in structural changes (in at least seven tumors each). Three tumors had one or two 11p- chromosomes, and, in other tumors, chromosome #11 had taken part in translocations or isochromosome formation, which, except in one tumor, resulted in a loss of short arm material. Also, there was a tendency for the presence of fewer than expected normal chromosomes #11. Chromosome #1 anomalies are common in most types of tumor; however, chromosome #11 abnormalities, particularly the loss of short arm material, are not common and may thus characterize carcinoma of the bladder, a finding that is of interest in view of the location of an oncogene, c-Ha-ras1, on 11p. Translocations probably involved chromosome #17 in four tumors. Structurally changed chromosomes #3 were seen in four tumors, including one or two 3q- chromosomes in two or possibly three tumors.

On the diploid state of the fish order Ostariophysi.

Our previous study on the order Ostariophysi was limited to members of the family Cyprinidae, suborder Cyprinidea. It was shown that the carp and the goldfish with 104 chromosomes and a DNA value of 50% that of mammals are tetraploid, as the diploid species of this family has 50–52 chromosomes and a 25% DNA value. In order to obtain some idea as to how many changes in DNA values and chromosome complements have occurred among diploid members of Ostariophysi, the study was expanded to cover members of the families Cobitidae and Characinidae of the suborder Cyprinidea as well as members of the families Ictarulidae and Loricaridae of the suborder Siluroidea. Diploid chromosome numbers varied from 50 to 98 and DNA values from 27–51% that of mammals. Apparently, diploid members of Ostariophysi underwent extensive chromosomal rearrangements as well as steady increases in DNA contents by regional duplication of chromosomal segments.

A 3-cM commonly deleted region in 6q21 in leukemias and lymphomas delineated by fluorescence in situ hybridization†

Deletions of the long arm of chromosome 6 (6q) are frequent chromosome aberrations in non‐Hodgkin lymphomas (NHLs) and acute lymphoblastic leukemias (ALLs). It is presumed that one or more tumor suppressor genes are localized on 6q. By means of fluorescence in situ hybridization (FISH), we attempted to detect and delineate deletions of 6q in leukemias and lymphomas. We performed FISH on 148 cases of lymphoma and acute leukemia using a panel of 36 YAC probes distributed from 6q12 to 6q27 and a centromeric probe of chromosome 6 as internal control. Deletions of 6q that included a 7‐cM commonly deleted region in 6q21 were detected in 59 patients who had B‐ and T‐cell low‐grade and high‐grade NHL and ALL. FISH with two YAC probes flanking this region was performed on an additional 97 cases of NHL and leukemia. Deletions in 6q21 were detected in an additional 21 cases. In five cases of high‐grade B‐ and T‐cell NHL and ALL, the deletion breakpoints were located within the commonly deleted region. To define the deletion breakpoints exactly and to narrow this region further, FISH was performed with six additional YAC probes that have been physically localized within this region. A 3‐cM (4–5 Mb) commonly deleted region in 6q21 was delineated. Our study suggests that this commonly deleted region harbors a putative tumor suppressor gene involved in the pathogenesis of both low‐grade and high‐grade NHL and ALL. Genes Chromosomes Cancer 27:52–58, 2000.