Marion C. Baker

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.

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.

Chromosome 1 in 26 carcinomas of the cervix uteri Structural and numerical changes

Cytogenetic studies on 26 carcinomas of the cervix showed that chromosome 1 was consistently involved in the changes: either one or more structurally abnormal chromosomes or a relative excess of normal chromosomes were present. Several types of structural change were repeatedly seen: short arm deletions (1p‐, in seven tumors); long arm isochromosomes (i(1q), in six tumors); and translocations of unidentified chromosomal material onto one of the arms (possibly in eleven tumors; in four of these, there was an additional C‐band on the long arm). In one tumor, there was a short arm isochromosome (i(1p)). The most consistent feature of the aneuploid complements of these tumors appeared to be the presence in excess of the centromeric region and at least part of the adjacent heterochromatin of chromosome 1. Cancer 44:604‐613, 1979.

Chromosome changes in 43 carcinomas of the cervix uteri

A summary of the chromosome changes in 43 carcinomas of the cervix studied by a direct technique showed that the most common anomaly was a small metacentric [in 77%, often in two copies: an i(5p) or possibly an i(4p)]. Others commonly involved in structural changes were: chromosome 1 (60%; most commonly an i(1q), 1p-, or translocation of part of 1q onto another chromosome); chromosome 17 (47%; translocations onto the short arm or long-arm isochromosomes), chromosome 11 (37%; translocations onto the short arm); chromosome 3 (26%; including 3p- and 31-); and chromosomes 2, 6, and 9 (each in 19%). Considering the four most frequent categories of markers--small metacentrics and markers derived from chromosomes 1, 17, and 11, none of which is specific for cervical carcinoma--almost any combination of these four might be present in a tumor (and at least one was present in all tumors) so that they were not mutually exclusive. Estimates of the average numbers of normal chromosomes based on representative karyotypes from 35 of the tumors showed that three chromosomes in particular were underrepresented (chromosomes 4, 11, and 14; 72-73% of the expected values), while chromosomes 3, 19, and 20 were those most highly represented (99-103%).

Nonrandom chromosome changes in carcinoma of the cervix uteri. I. Nine near-diploid tumors.

Chromosome analysis of G- and C-banded preparations of tumor material, processed by a direct method, from nine primary carcinomas of the cervix with modal chromosome numbers in the range 41-49 showed the nonrandom involvement of certain chromosomes in structural and numerical changes. Besides chromosome No. 1 (six tumors), structural changes involved chromosomes No. 11 (five tumors with variable breakpoints and translocation partners), No. 3 (three tumors) No. 6 (three tumors), and No. 17 (17p+ in two tumors). A small metacentric (present in duplicate in most metaphases of one tumor), which may have been a 5q- (?) (with an interstitial long arm deletion), was seen in five tumors. Additional normal chromosomes included chromosomes No. 1 (one tumor without structural changes in this chromosome showing trisomy 1) and No. 3 (four tumors showing trisomy in the absence of structural changes involving this chromosome). Losses commonly affected the B, D, and G groups, particularly chromosomes No. 13 (three tumors) and No. 21 (six tumors), as well as chromosome No. 18 (four tumors). Two X chromosomes were present in all tumors except the two with the lowest modal numbers, both of which lacked an X chromosome.

Chromosome analysis of three seminomas

Each of three seminomas revealed chromosome #1 and #12 structural changes in direct preparations and short-term cultures. The #1 changes involved duplication of 1q and loss of 1p; in two, the breakpoint was in the heterochromatic region. The anomaly in #12 was a short arm isochromosome, usually present in duplicate. In one tumor, these were the only structural changes; in the other two, there was also involvement of #7, with extra copies of 7p. In one of these two tumors, a heterochromatic minute was identified after C-banding, and in the other, aside from two different markers containing part of #7, there was a dicentric derived from two chromosomes #15; this tumor proved to be prognostically unfavorable. Three normal chromosomes #1 and XXY sex chromosomes were present in each tumor. Chromosomes #11 and #13 were generally underrepresented, and #12 and #19-22 were over-represented.

Chromosome 7q deletions: Observations on 13 malignant tumors

Deletions of the long arm of chromosome 7, with breakpoints varying from q11 to q34, are described in 13 malignant tumors, including three carcinomas of the prostate, three colorectal carcinomas, and four testicular germ cell tumors. In two of the tumors, the chromosome also had a deletion of 7p. Review of the literature shows that 7q- chromosomes have been detected in various tumor types and are particularly common in benign and malignant mesothelial tumors, secondary leukemias, testicular cancers, and carcinomas of the ovary and prostate. Their significance may lie in loss of an unknown tumor-suppressor gene situated distally on 7q.

A metastatic malignant melanoma with 24 chromosomes.

SummaryA metastatic malignant melanoma in a female aged 45 showed a modal chromosome number of 24. G-banding suggested the following deviations from a haploid complement: trisomy for 1q and disomy for 6p and the whole of chromosome 7.