Biomedical subjects

Raymond Lai

Publications and source records attributed to Raymond Lai.

60 records · Page 4Linked to original sources

PubMed2002

Immunohistochemical expression of the transcription factor DP-1 and its heterodimeric partner E2F-1 in non-Hodgkin lymphoma.

DP-1 is a G1 cell cycle-related protein that forms heterodimers with E2F, a family of transcriptional factors regulating the expression of genes important for G1 to S progression. Although the exact role of DP-1 is not well understood, it has been shown to stabilize DNA binding of E2F proteins. By immunohistochemistry, the authors examined the expression of DP-1 in lymphoid tissues, including 8 cases of reactive follicular hyperplasia and 69 cases of B-cell non-Hodgkin lymphoma. The expression of the cell cycle-related proteins E2F-1 and Ki-67 was also assessed. Scoring was based on the proportion of labeled nuclei (1-10%, 11-25%, 26-50%, and > 50%). In reactive follicular hyperplasia, staining for DP-1, E2F-1, and Ki-67 was largely confined to the germinal centers. All 25 cases of follicular lymphoma, regardless of grade, had a high proportion (> 50%) of DP-1-positive cells but a lower proportion of cells marking for E2F-1 and Ki-67 (P < 0.001). The diffuse large B-cell lymphomas (n = 24) had high DP-1 and Ki-67 scores but low E2F-1 scores (P < 0.001). Small lymphocytic (n = 10), marginal zone (n = 3), and mantle cell lymphomas (n = 5) contained relatively low proportions of cells labeled for all three markers. Precursor B-cell lymphoblastic lymphoma (n = 2) displayed high proportions of cells positive for DP-1, Ki-67, and E2F-1 (> 50% in both cases). Except in follicular center cell lesions, DP-1 expression generally correlated with that of Ki-67. However, the expression of DP-1 was discordant with that of E2F-1 in benign and malignant follicular center cells, suggesting that DP-1 may have functions other than facilitating E2F-1-dependent gene regulation and cell cycle progression in these neoplasms.

Cell Cycle Proteins↗

PubMed2002

Mantle cell lymphoma with 8q24 chromosomal abnormalities: a report of 5 cases with blastoid features.

The t(11;14)(q13;q32) resulting in cyclin D1 overexpression is consistently present in mantle cell lymphoma. However secondary chromosomal aberrations are also extremely common. Of these, 8q24 abnormalities associated with the t(11;14) are rare. Over the course of 10 years at M.D. Anderson Cancer Center, we identified five cases of mantle cell lymphoma in which conventional cytogenetic analysis revealed complex karyotypes, including the t(11;14) and 8q24 abnormalities: one with t(8;14)(q24;q32), one with t(2;8)(q13;q24), and three with add(8)(q24). We performed fluorescence in situ hybridization (FISH) studies on all cases. In the case with the t(8;14), IgH/myc fusion signals were identified, and in the case with the t(2;8), split c-myc signals were detected. In the three cases with add(8)(q24), one case had split c-myc signals and two cases had three copies of c-myc. Thus, the c-myc gene was involved in all cases. All five neoplasms had blastoid morphologic features, and four cases, including the cases with the t(8;14) and t(2;8), had leukemic involvement. We conclude that 8q24 abnormalities involving the c-myc gene are uncommon secondary abnormalities that occur in a subset of mantle cell lymphomas. C-myc gene abnormalities are associated with blastoid cytologic features and also may be associated with leukemic involvement.

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PubMed2002

Precursor T-cell acute lymphoblastic leukemia in adults: age-related immunophenotypic, cytogenetic, and molecular subsets.

We analyzed the clinicopathologic and molecular findings in 26 adults (age 16-72 years) with T-cell acute lymphoblastic leukemia (T-ALL) and observed features that correlated with age. Patients older than 60 years (n = 5) had a low frequency of hepatosplenomegaly (0 [0%]), anterior mediastinal mass (1 [20%]), and lymphadenopathy (2 [40%]), and completely responded to chemotherapy (4 of 4). The T-ALL in this group commonly expressed myeloid antigens (4 [80%]), had lineage-inappropriate gene rearrangements (2/3 [67%]) and chromosome 2 deletion (3/4 [75%]), and exclusively used the V(III) or V(IV) families of the T-cell receptor (TCR) gamma gene. In comparison, patients 16 to 60 years old (n = 21) more commonly had an anterior mediastinal mass (8 [38%]), hepatosplenomegaly (10 [48%]), and lymphadenopathy (16 [76%]). The tumors in these patients commonly used the TCR gamma gene VI or V(II) families (17/25 total rearrangements [68%]). Myeloid antigen expression (5 [24%]) and lineage inappropriate gene rearrangements (4/15 [27%]) were uncommon. Within this group, CD1a expression correlated with age 28 to 60 years. These results illustrate considerable age-related heterogeneity in adult T-ALL, which may reflect differences in tumor cell maturation.

Adolescent↗

PubMed2002

Apoptotic rate in peripheral T-cell lymphomas. A study using a tissue microarray with validation on full tissue sections.

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of non-Hodgkin lymphomas with a wide spectrum of clinicopathologic features, and apoptosis mechanisms may have a role in lymphomagenesis. We assessed apoptotic rate (AR) in 112 PTCLs using a tissue microarray developed in our laboratory and a modified terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. The mean AR was 1.47% +/- 1.38% for the entire group of PTCLs (range, 0.06%-5.15%), and AR varied significantly among different tumor types. In mycosis fungoides, the mean AR was 0.74%; angioimmunoblastic T-cell lymphoma, 1.02%; PTCL, not otherwise specified, 1.38%; cutaneous anaplastic large cell lymphoma (ALCL), 1.41%; anaplastic lymphoma kinase protein (ALK)-negative ALCL, 1.43%; extranodal natural killer/T-cell lymphoma of nasal type, 2.04%; ALK-positive ALCL, 2.95%; and enteropathy-type T-cell lymphoma, 3.06%. Mean AR was higher in PTCL with large cell vs small/medium cell morphologic features (1.66% +/- 1.1% vs 0.99% +/- 1.0%). In a subset of 33 PTCLs, the tissue microarray results comparedfavorably with those obtained in full tissue sections. We conclude that the highest ARs in PTCLs are found in enteropathy-type T-cell lymphoma and ALK-positive ALCL, and that AR can be assessed reliably by using a tissue microarray.

Anaplastic Lymphoma Kinase↗

PubMed2002

Acute lymphoblastic leukemia in elderly patients the Philadelphia chromosome may not be a significant adverse prognostic factor.

Acute lymphoblastic leukemia (ALL) in elderly patients (59 years or older) carries a poor prognosis, and this finding may be attributed to the relatively high frequency of the Philadelphia chromosome (Ph). To test this hypothesis, we reviewed the clinicopathologic features of 23 consecutive, newly diagnosed elderly patients with ALL (14 men, 9 women, aged 59-92 years) uniformly treated at our institution and compared the Ph+ and Ph- groups. Conventional cytogenetic data were available for 21 of 23 cases; 7 (33%) were Ph+. All Ph+ cases were of precursor B-cell type. The remaining 16 tumors were of precursor B-cell (10), mature B-cell (2), precursor T-cell (3), and mixed precursor T-cell/B-cell (1) type. Ph+ and Ph- groups did not differ significantly in median survival (13.4 months vs 19.0 months) or other variables studied. The Ph may not be a significant adverse prognostic factor in ALL in elderly patients.

Aged↗

PubMed2002

Chronic lymphocytic leukemia with t(14;18) and trisomy 12.

The chromosomal abnormality t(14;18) is most commonly associated with neoplasms of follicular center cell origin. However, t(14;18) also has been reported in rare cases of chronic lymphocytic leukemia (CLL). In 2215 cases of CLL studied by conventional cytogenetics in our institution, we identified 2 cases of CLL carrying t(14;18). Both patients were men, aged 52 and 71 years at the time of diagnosis. One patient presented with leukemia and the other primarily with nodal disease. In addition to t(14;18), trisomy 12 (+12) was identified in the same clone in both cases. Atypical morphologic features were identified: case 1 contained more than 15% lymphoid cells with cleaved nuclei, whereas case 2 contained more than 15% plasmacytoid lymphoid cells. The immunophenotype of case 2 was also unusual for CLL, showing weak CD23 expression and FMC7 positivity. We identified 6 other t(14;18)-carrying CLL cases in the literature; 2 had t(14;18) as the sole abnormality and 2 contained +12 as the additional abnormality. To conclude, cases of CLL carrying t(14;18) are exceedingly rare, and +12 appears to be the most common cytogenetic abnormality coexisting with t(14;18) in CLL.

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