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Biomedical subjects

S N Sait

Publications and source records attributed to S N Sait.

At least 37 records · Page 2Linked to original sources

The kinase insert domain receptor gene (KDR) has been relocated to chromosome 4q11-->q12.

Through in situ hybridization of a genomic DNA probe to metaphase chromosomes, we have localized the KDR gene to 4q11-->q12. This is the same locus as that for two other receptor tyrosine kinases, PDGFRA and KIT. This location for KDR differs from that which we previously reported using a cDNA probe. Using cDNA probes for both KDR and KIT identifies a locus at 4q31-->q32 which may uncover another cluster of receptor tyrosine kinase genes.

Chromosome Mapping↗

Localization of Beckwith-Wiedemann and rhabdoid tumor chromosome rearrangements to a defined interval in chromosome band 11p15.5.

Chromosome rearrangements have provided useful landmarks to identify disease loci and have served as starting points for positional cloning strategies for candidate genes. We have used fluorescence in situ hybridization (FISH) and pulsed-field gel electrophoresis (PFGE) to map three Beckwith-Wiedemann syndrome (BWS) breakpoints and a rhabdoid tumor breakpoint more precisely. These breakpoints mapped to the interval between D11S679 and the insulin-like growth factor 2 (IGF2) gene on 11p15.5. A cosmid (c15-2) was identified that mapped centromeric to the BWS t(11;16) and the rhabdoid tumor-associated t(11;22), telomeric to the BWS t(11;22), and was found to span the BWS-associated inv(11) breakpoint. Pulsed-field gel analysis placed all four breakpoints into a 250-675 kb interval distal to D11S679 and at least 270 kb centromeric to the IGF2 and H19 loci. These data locate all three BWS rearrangements and the rhabdoid tumor t(11;22) breakpoint in the same region of 11p15.5, suggesting that they may be affecting the same locus or closely linked loci. Cosmid c15-2 provides a well-defined starting point in the search for candidate disease genes.

Beckwith-Wiedemann Syndrome↗

Characterization of two 11q23.3-11q24 deletions and mapping of associated anonymous DNA markers.

Translocations in bands 11q23.3-11q24 are associated with several human cancers, including acute lymphoid and acute myeloid leukemias (AML) and Ewing's sarcoma. We have characterized two independent deletions in this region, one derived from a patient with AML who previously had a T-cell lymphoma, and another from a Wilms' tumor patient. Cytogenetic analysis of the ML-2 cell line established from the malignant cells of the AML patient indicated that one chromosome 11 homolog had an interstitial deletion, del(11) (q23q24), and the remaining homolog was involved in a recurring translocation, t(6;11) (q27;q23). According to karyotype analysis on the Wilms' tumor patient (EH), one chromosome 11 was normal and the other carried an interstitial deletion at 11q23.3-11q25. Somatic cell hybrids segregating the EH deletion (EHR4) and the ML-2 deletion (MLR4) have been isolated. The EH deletion is distal to the MLL probe recently associated with 11q23.3 leukemia breakpoints (Ziemin-van der Poel et al.: Proc Natl Acad Sci USA 88:10735-10739, 1991). The ML-2 deletion could involve the MLL gene at a point distal to other breakpoints within MLL. Both deletions include the Ewing's sarcoma breakpoint at 11q24.1. By Southern blot analysis we identified three anonymous DNA markers (D11S272, D11S273, and D11S219) and the ETS/oncogene, which map within each deleted region. These markers are conserved based on zoo blot analysis, and they are valuable for physical mapping and genetic characterization of a region that may code for gene products associated with growth control and tumor suppression in a variety of cancers.

Animals↗

Deletion of chromosome 22 without bcr rearrangement and without juxtaposition of c-abl in a case of acute myeloid leukemia.

We describe a patient with acute myeloid leukemia (AML) who had a deletion of chromosome 22 at q11 as a sole chromosomal abnormality, resulting in the karyotype 46,XY,del(22)(q11). Southern blot analysis showed no bcr rearrangement and fluorescence in situ hybridization indicated no juxtaposition of c-abl. This study indicates that molecular events other than bcr rearrangement and c-abl juxtaposition were involved in leukemogenesis in this patient. We hypothesize that a tumor suppressor candidate gene may be located on the long arm of chromosome 22; its loss may lead to malignant transformation.

Blotting, Southern↗

A uterine leiomyoma showing both t(12;14) and del(7) abnormalities.

The involvement of chromosomes 12 and 14 in uterine leiomyomas has been well established. However, in a recent report of only a del(7)(q22.1q31.32) or (q11.2q22.3) in two cases of typical uterine leiomyoma, Boghosian et al. hypothesized that this could represent a cytogenetic subgroup of uterine leiomyomas. We report a case of uterine leiomyoma with both the t(12;14) and del(7) in all the cells examined and discuss the implications of this in terms of critical chromosomal rearrangements underlying the route to benign cellular proliferation.

Chromosome Deletion↗

Consistent chromosome changes in leiomyosarcoma.

Karyotypic analysis of a leiomyosarcoma of the retroperitoneum revealed some structural and numerical changes. Review of the literature showed that some of these changes, namely involvement of 1p13 and 11p13 and monosomy 9, 18 and 22 seemed to occur frequently. These changes could be characteristic of leiomyosarcoma and define a cytogenetic subgroup within this tumor entity.

Chromosome Aberrations↗

An acquired Robertsonian translocation dic(14;14)(p11;p11) in a patient with a myelodysplastic syndrome following treatment of multiple myeloma.

Acquired Robertsonian translocations are considered to be very rare chromosome changes in human malignancy, and only three cases have been described. We report a dic(14;14)(p11;p11) in a patient with myelodysplastic syndromes (MDS) following treatment for multiple myeloma. This patient also had other complex chromosomal abnormalities. The pattern of karyotype evolution in this patient was established by a series of cytogenetic studies. The relationship of the complex chromosomal changes to MDS following treatment for multiple myeloma is discussed.

Aged↗

Chromosome changes in metastatic human melanoma.

Cytogenetic studies were performed on human malignant melanoma cells from eight metastatic lesions. Five tumors displayed near-triploid and three near-diploid chromosome numbers. Chromosomes #1, #6, #7, followed by #2 and #9, were found to be most frequently involved in structural aberrations. Aberrations involving chromosome #1, with deletions or translocations of 1p, involving region 1p12-1p22 in seven of eight breakpoints of the p arm were observed. Seven of nine breakpoints of 6q were located at region 6q15-6q21. Most of the breakpoints on chromosome #7 occurred near the centromeric region. All tumors had additional chromosome material involving 1q, chromosome #7 (7q in two tumors), and in five tumors an increased dose of chromosome #6 (6p in one tumor). The nonrandom breakpoints of these and other chromosomes involved diverse bands, including loci of oncogenes and fragile sites. The observation of nonrandom chromosomal changes in advanced malignant melanoma suggests that genes important in the progression of melanoma are located on chromosomes #1, #6, and #7.

Adult↗

A t (11;21) (13;q22) in Ph-positive chronic myelogenous leukemia.

Reciprocal translocations, in addition to that of the Ph chromosome, though rare, have been reported in chronic myelogenous leukemia (CML). We describe here a case of Ph-positive CML with a new translocation, t (11;21) (q13;q22), and missing Y, which were present both during transformation to the blastic crisis and in the subsequent reversion to the chronic phase. The possible significance of this abnormality is discussed.

Aged↗

Complex cytogenetic changes in Ph-negative chronic myelogenous leukemia.

A Ph-negative chronic myelogenous leukemia (CML) with t(3;7)(q21;q32), t(4;9)(q21;q34), and del(8)(q22) is reported. This case is rather unusual for Ph-negative CML in being associated with complex chromosome changes. The patient was diagnosed as in the accelerated phase of CML. It will be important to study this malignant disorder in detail cytogenetically and molecularly in order to ascertain its nature and place among the myeloproliferative disorders.

Adult↗

Translocation t(1;22) in congenital acute megakaryocytic leukemia.

Acquired chromosomal abnormalities have been reported in 80 patients with congenital acute leukemia, the commonest being t(4;11). We report here a case of acute megakaryocytic leukemia with a rare translocation of t(1;22)(p13.3;q13.3). The course of the disease was short, with the patient surviving less than a year after the initial diagnosis.

Chromosomes, Human, Pair 1↗

Translocation t(6;9)(p22.3;q34) in myelodysplastic syndrome--refractory anemia with excess blasts.

A 69-year-old male patient with refractory anemia with excess blasts (RAEB) was found to have a consistent chromosomal abnormality, t(6;9)(p22.3;q34), in the bone marrow and unstimulated peripheral blood cells. Twenty patients with t(6;9) and leukemia have been reported; some of them had a myelodysplastic syndrome (MDS) before developing overt ANLL. Our patient was still in the MDS stage when the t(6;9) was found. This result suggests that t(6;9) represents one of the pathways from MDS to leukemia in patients with ANLL.

Aged↗

Recurrent involvement of 11q13 in acute nonlymphocytic leukemia.

Rearrangements of 11q have been associated with acute nonlymphocytic leukemia (ANLL), particularly M4 and M5 (FAB classification). Though 11q23 is most often involved, 11q13 is also affected. We report two cases of ANLL with translocations involving band 11q13.

Aged↗

A t(1;11) in acute nonlymphocytic leukemia FAB type M4.

Abnormalities involving the long arm of chromosome #11 have been shown to be involved in a high proportion of acute nonlymphocytic leukemias, specifically FAB types M4 and M5. In particular, band 11q23 seems to be preferentially affected. Reported herein is a case of acute nonlymphocytic leukemia type M4 showing a t(1;11)(q21;q23).

Acute Disease↗

Trisomy 4: an entity within acute nonlymphocytic leukemia.

Trisomy 4 is a newly recognized primary chromosome change in leukemia. Five cases of acute nonlymphocytic leukemia (ANLL) are described from the United States and France. As in cases from Belgium, the only chromosome abnormality detected in the leukemic cells was trisomy 4. This was associated preferentially with ANLL of the M4 type (by FAB classification): acute myelomonocytic leukemia.

Acute Disease↗