Publications by authors named "Gopalrao V N Velagaleti"

While macrophage phagocytosis is an immune defense mechanism against invading cellular organisms, cancer cells expressing the CD47 ligand send forward signals to repel this engulfment. Here we report that the reverse signaling using CD47 as a receptor additionally enhances a pro-survival function of prostate cancer cells under phagocytic attack. Although low CD47-expressing cancer cells still allow phagocytosis, the reverse signaling delays the process, leading to incomplete digestion of the entrapped cells and subsequent tumor hybrid cell (THC) formation.

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Background: Mosaicism for chromosomal structural abnormalities, other than marker or ring chromosomes, is rarely inherited.

Methods: We performed cytogenetics studies and breakpoint analyses on a family with transmission of mosaicism for a derivative chromosome 8 (der(8)), resulting from an unbalanced translocation between the long arms of chromosomes 8 and 21 over three generations.

Results: The proband and his maternal half-sister had mosaicism for a der(8) cell line leading to trisomy of the distal 21q, and both had Down syndrome phenotypic features.

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Although the 5q- syndrome is common in both de novo and treatment related myelodysplastic syndrome (MDS) and the World Health Organization defined 5q- syndrome as a specific type of MDS, it is less common in acute myelogenous leukemia (AML). Recently, it was suggested that AML with diploidy/tetraploidy and/or 5q alterations may be associated with the cryptic translocation, t(7;21)(p22;q22) resulting in RUNX1-USP42 gene fusion and this association may have been underestimated. Here, we report another case of de novo AML with cryptic t(7;21)(p22;q22) associated with a 5q deletion.

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Proteasome inhibitor (PI) therapy has improved the survival of multiple myeloma (MM) patients. However, inevitably, primary or acquired resistance to PIs leads to disease progression; resistance mechanisms are unclear. Obesity is a risk factor for MM mortality.

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One of the well-known hallmarks of cancer is genomic instability. Although gradualism is a well-established process of cancer evolution, recent studies have shown that chromothripsis or chromoanasynthesis can result in complex genomic rearrangements by a single catastrophic event rather than several incremental steps. These two novel phenomena suggest an evolutionary modality for cancer cells to circumvent individual mutational events with one simultaneous shattering of chromosomes or chromosome regions resulting in the random reassembling of shattered genetic material to form complex derivative chromosomes.

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Introduction: Mast cell leukemia (MCL) is a rare variant of systemic mastocytosis. Most cases of mast cell leukemia do not have cytogenics performed. Furthermore, there is no consistent chromosomal abnormality identified in MCL.

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We present a case of fetoplacental discrepancy in a second-trimester fetus with normal karyotype in amniotic fluid and two different Robertsonian translocations in placenta. A 41-year-old woman of Middle-Eastern origin, gravida 2, para 1, underwent amniocentesis at 16-week gestation because of advanced maternal age. Amniotic fluid karyotype showed a normal 46,XX karyotype with a homozygous inv(9).

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We previously hypothesized that cytogenetic abnormalities precede morphological abnormalities in developing malignant conditions. In this context we evaluated additional cases to further confirm that hypothesis. We report on 2 additional cases in which clonal cytogenetic abnormalities were observed in otherwise morphologically normal samples.

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Chondromyxoid fibroma (CMF) is a rare cartilaginous tumor of bone. It typically presents in the long tubular bones and to a lesser extent in the small bones of the hands and feet of young adults. To date, several cytogenetic abnormalities have been described in association with CMF.

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Complex chromosome rearrangements (CCRs) are structural abnormalities involving >2 chromosomes or >3 breakpoints. It has been suggested that the probability of imbalance increases as the number of breakpoints increase. Here we report a 7-month-old, Hispanic girl presenting with cleidocranial dysplasia (CCD) who was found to have a complex chromosome rearrangement of chromosome 6.

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Oncogene amplification resulting in aberrant expression, although common in solid tumors, is rare in acute myeloid leukemia (AML) and is mostly associated with amplification of MYC, RUNX1, and MLL genes. Retinoic acid receptor alpha (RARA) and other target sequences at 17p11.2 often represent the amplicons expressed in breast cancer, not in AML.

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Uterine leiomyomas are smooth muscle tumors most commonly seen in middle-aged women. Approximately 10% of these tumors contain rearrangements of the chromatin-remodeling gene HMGA2 at the chromosome band 12q14.3.

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Goldenhar syndrome, also called hemifacial microsomia or oculo-auriculo-verterbal dysplasia (OAVS) (MIM 164210), is a birth defect involving the first and second branchial arch derivatives with an incidence of 1/5000. The variable phenotype includes mostly unilateral deformity of the external ear and small ipsilateral half of the face with epibulbar dermoid and vertebral anomalies. A genome-wide search in one family suggested linkage to a region of 10.

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We describe two cases of trisomy 2. The first case is a child with mosaic trisomy 2 who presented with mental retardation, multiple congenital anomalies, and dysmorphic findings similar to Pallister-Killian syndrome. The second case was an acardiac and acranial fetus with complete trisomy 2.

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Gastroesophageal reflux (GER) occurs when gastric contents travel back into the esophagus through the esophageal sphincter. GER is very common in infants with most growing out of it, but some continue to have chronic symptoms throughout childhood and adulthood. A gene for severe pediatric gastroesophageal reflux disease (GERD) was identified by linkage analysis and was mapped to chromosome 13.

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Approximately, 20 cases of interstitial deletions of 9q have been reported in the literature spanning the breakpoints from 9q21 to 9q34. Unlike the 9q subtelomeric deletions, the interstitial deletions do not demonstrate a specific recognizable phenotype, although the majority of patients had microcephaly. Lack of precise molecular delineation of the extent of deletions in the published cases makes it difficult to develop an accurate genotype-phenotype correlation.

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Partial trisomy 7p with partial monosomy 9p is a rare disorder with only 3 cases reported. Both these abnormalities i.e.

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Human chromosome 8p is prone to recurrent rearrangements with inv dup del(8p) being most common. Each of these recurrent rearrangements is associated with different clinical manifestations. Some of these recurrent rearrangements at 8p are mediated by an 8p submicroscopic paracentric inversion between the olfactory gene clusters present in one of the parents.

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Cytogenetic evaluation of bone marrow and neoplastic tissues plays a critical role in determining patient management and prognosis. Here, we highlight two cases in which the cytogenetic studies challenge the common practice of using hematologic and morphologic changes as key factors in malignant disease management. The first case is that of a lymph node sample from a 40-yr-old non-Hodgkin's lymphoma (NHL) patient sent for determination of disease progress.

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Cytogenetic and molecular studies have shown that approximately 80% of cases of alveolar rhabdomyosarcoma (ARMS) have consistent chromosomal translocation of either t(2;13) or t(1;13), resulting in either PAX3-FKHR or PAX7-FKHR gene fusions. However, 20% of the cases diagnosed histologically are negative for these fusion genes. The clinical and pathological properties of the so-called fusion gene negative tumors remain to be defined.

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Chromosome deletions involving 1p36 are the most common known terminal rearrangements occurring at a frequency of approximately 1 in 5,000 live births. In contrast, duplications of the same region have been reported rarely. We describe a familial rearrangement der(1)del(1)(p36.

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Objective: To estimate the frequency of subtelomeric rearrangements in patients with sporadic and non-syndromic idiopathic mental retardation (IMR).

Methods: A total of 18 IMR patients were taken for the study. Selection criteria included no known syndromes or chromosomes abnormalities and known causes of IMR.

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Non-allelic homologous recombination (NAHR) between low-copy repeats (LCRs) has been implicated recently in somatic rearrangements including isochromosome i(17q), which is associated with hematologic malignancies as well as solid tumors. In hematological malignancies, the most common i(17q) breakpoint results from LCR-mediated NAHR, which creates a dicentric chromosome, idic(17)(p11.2).

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