Localization of the oncogene c-Ha-ras1 outside the aniridia-Wilms' tumor-associated deletion of chromosome 11(del 11p13) using somatic cell hybrids

Reduction to homozygosity of genes on chromosome 11 in human breast neoplasia

The somatic loss of heterozygosity for normal alleles occurring in human tumors has suggested the presence of recessive oncogenes. The results presented here demonstrate a loss of heterozygosity of several genes on chromosome 11 in primary breast tumors. Restriction fragment length polymorphism analysis of these DNAs further suggests that the most frequent loss of sequences in breast tumors occurs between the beta-globin and parathyroid hormone loci on the short arm of chromosome 11. The loss of heterozygosity for chromosome 11 loci has a significant association with tumors that lack estrogen and progesterone receptors, grade III tumors, and distal metastasis.

Familial isolated aniridia associated with a translocation involving chromosomes 11 and 22 [t(11;22)(p13;q12.2)]

Isolated aniridia segregated as an autosomal dominant trait in a family with 11 affected members spanning five generations. Four of the eight individuals studied had aniridia associated with glaucoma and cataracts. Cytogenetic studies revealed an apparently balanced reciprocal translocation between chromosomes 11 and 22 [t(11;22)(p13;q12.2)], while four unaffected relatives had normal karyotypes. There is no evidence of Wilms tumor or genitourinary abnormalities in any members of the family. Restriction enzyme analysis of the human catalase gene revealed no abnormalities in the individuals with the translocation. A summary of phenotypic abnormalities in 61 cases associated with aniridia is presented, as well as a comparison of breakpoints in 44 cases of 11p deletion. These data indicate that single breaks at 11p13 are associated with isolated aniridia, while deletion of 11p13 results in aniridia combined with Wilms tumor, genitourinary abnormalities, and/or mental retardation.

The cytogenetics of Wilms' tumor

A close association has been demonstrated between the congenital deletion 11p13 and predisposition to Wilms' tumor. Recent cytogenetic studies on Wilms' tumor cells from normal children strongly suggests that somatic changes in the short arm of chromosome #11 play an important role in the development of this tumor. The application of improved cytogenetic techniques coupled with molecular biologic analysis may help resolve questions regarding the requirement of additional changes (to alterations of 11p13) in order to evoke complete transformation leading to malignancy.

Chromosomal changes in secondary leukemias of childhood and young adulthood

The increasing success of antineoplastic therapy has resulted in a growing number of long-term survivors. These people are at risk for complications of the therapy itself. Among these induced acute nonlymphoid leukemia (ANLL) has been both common and often lethal. We reviewed 72 recently reported patients under 30 years of age at the time of initial diagnosis who developed a secondary, karyotypically defined leukemia. Fifty-eight patients contracted ANLL a mean of 4 1/2 years from the initial diagnosis. In 25 patients, this was preceded by a preleukemic phase characterized by a hypercellular bone marrow with abnormal precursors, often accompanied by peripheral pancytopenia, that lasted a mean of 6 months. Three additional patients died in this preleukemic phase. In all 61, the most common chromosomal abnormalities were numerical errors. Twenty-four patients had a hypodiploid karyotype, most often in those in whom the primary diagnosis was lymphoma (22 of 43). The most common chromosomes missing in whole or in part were number 7 (18 patients), number 5 (8 patients), number 17 (5 patients), and number 21 (4 patients). The anomalies were frequently multiple and complex. Monosomy 7 figured particularly strongly and may be similar to a karyotypically identical myeloproliferative disorder characterized by micromegakaryocytes, giant platelets, and abnormal granulocyte function arising de novo in children. These findings are similar to those in older patients with ANLL induced by environmental carcinogens or antineoplastic therapy. They are different from the karyotypic changes seen in de novo ANLL in children and young adults, suggesting a different etiology. Also, they reinforce the need to find less leukemogenic treatment programs.