Sox9, a master regulator of chondrogenesis, distinguishes mesenchymal chondrosarcoma from other small blue round cell tumors.

Over the last decade, a number of "master regulator" genes that control distinct pathways of mesenchymal differentiation have been discovered. These genes are expressed early during embryogenesis and initiate a cascade of gene expression responsible for specific cell lineage commitment. Thus, identification of their products may allow the classification of seemingly primitive, morphologically uncommitted tumors such as small blue round cell tumors. The transcription factor Sox9 has been demonstrated to be a master regulator of the differentiation of mesenchymal cells into chondrocytes. For this reason, we examined the utility of Sox9 in distinguishing mesenchymal chondrosarcoma (a small cell malignancy thought to be derived from primitive chondroprogenitor cells) from other primitive small cell malignancies. Representative sections from 90 cases of small blue round cell tumors (22 mesenchymal chodrosarcoma, 10 neuroblastomas, 11 rhabdomyosarcomas, 9 Ewing's sarcomas/primitive neuroectodermal tumors, 5 desmoplastic small round cell tumors, 7 small cell carcinomas, 6 Merkel cell carcinomas, 6 small cell osteosarcomas, 7 diffuse large B-cell lymphomas, 7 lymphoblastic leukemias/lymphomas, and 5 extraskeletal myxoid chondrosarcomas) were immunohistochemically stained with antibodies to Sox9 protein. All but 1 mesenchymal chondrosarcoma showed positive nuclear staining in both primitive mesenchymal and cartilaginous components of the tumor. All other types of small blue round cell tumors, as well as the lymphomas and leukemias, were negative for Sox9 protein. These findings confirm that mesenchymal chondrosarcoma has phenotypic features corresponding to the early condensational phase of cartilaginous differentiation. More important, Sox9 may serve as a useful tool in the differentiation of small cell malignancies.

Cutaneous lymphoblastic lymphoma in children: report of six cases with precursor B-cell lineage.

Precursor B lymphoblastic lymphomas (B-LBL) are generally rare, but appear to have a higher incidence in children than in adults. In this report, we describe in detail six cases of B-LBL presenting with cutaneous lesions. Three occurred in the scalp, one in the skin of the thigh, one in the skin of the face and breast, and one in the subcutaneous tissue of the orbit. All six patients are females ranging in age at presentation from 5 to 15 years (mean = 9.6). None of the cases had bone marrow involvement, while two had bone involvement (maxilla, distal tibia, and distal humerus in one case, and distal tibia and orbital bone in another case); only one case had lymphadenopathy (retroperitoneal). Immunohistochemical staining showed positivity for CD79a and CD43 in all six cases. LCA and L26 positivity were also each seen in one case. Staining for MIC-2 (CD99) showed strong positivity in three cases. Vimentin was positive in four cases and TdT was positive in all five patients tested. Staining for keratin, UCHL-1, or CD30 was not encountered. Cases in which cell marker studies by flow cytometry were performed showed positivity for CD10, CD19 with negative CD20, pan-T-cell, and myeloid markers. The five patients who received multiagent chemotherapy are alive with follow-up intervals of 2 to 18 years. Two patients had local recurrences and were given radiation therapy (one with repeating multiagent chemotherapy). One patient (diagnosed in 1962) died of disseminated disease; she had been treated with radiation therapy and 6MP only. Cutaneous B-LBL must be included in the differential diagnosis of small blue cell tumors, especially in children. In contrast to its T-cell counterpart, B-LBL occurs more frequently in females, tends to present as skin or bone lesions, and is associated with a potential cure, even in cases that relapse.

Precursor B-cell lymphoblastic lymphoma: a predominantly extranodal tumor with low propensity for leukemic involvement.

Precursor B-cell lymphoblastic lymphoma (B-LBL) is uncommon and accounts for less than 10% of cases of lymphoblastic lymphoma. We collected 25 cases of B-LBL, occurring in children and adults, and report the clinical and histologic features. Patients with concurrent precursor B-cell acute lymphoblastic leukemia (B-ALL) or a history thereof were excluded. There was no evidence of bone marrow disease at the time of diagnosis in 23 patients; two patients had focal (<5%) involvement. Immunophenotypic analysis was performed in all cases using flow cytometry or immunohistochemical methods. The treatment and survival data available for a subset of patients with B-LBL were compared with those from a series of patients with B-ALL at our institution. The median age was 20 years (range, 5-68 yrs); 22 (88%) patients were younger than 35 years of age. There were 17 males and 8 females. The primary sites of disease were skin (nine cases), bones (five cases), soft tissue (four cases), lymph nodes, (three cases), breast (two cases), stomach and colon (one case), and mediastinum (one case). Clinical stage was stage I in 13 cases, stage II in seven cases, stage III in three cases, and stage IV in two cases. Histologically, each neoplasm was diffuse and composed of small to medium-sized lymphoid cells with blastic nuclear chromatin and a high mitotic rate. All cases were positive for B-cell antigens and terminal deoxynucleotidyl transferase. Thirteen (76.4%) of 17 cases analyzed were positive for CD10 and 13 (54.1%) of 24 cases assessed were positive for CD20. Of 14 patients with available survival data, all achieved complete clinical response after combination chemotherapy (13 patients) or surgical excision followed by local irradiation (one patient). Five (35.7%) patients subsequently relapsed, including the patient who had received only irradiation, and four of these patients died after a median survival time of 60 months. None of the patients had leukemia, although one patient developed extensive bone marrow involvement. Nine patients remained in complete remission and were alive at the last follow up (range, 6-144 months). Unlike precursor T-cell lymphoblastic lymphoma, which commonly involves lymph nodes and the mediastinum, B-LBL usually involves extranodal sites, most often the skin, and rarely presents as a mediastinal mass. With aggressive chemotherapy, patients with precursor B-LBL rarely develop leukemia and appear to have a better prognosis than do patients with B-ALL.

BCL-1 (PRAD-1/cyclin D-1) overexpression distinguishes the blastoid variant of mantle cell lymphoma from B-lineage lymphoblastic lymphoma.

The blastoid variant of mantle cell lymphoma (MCL-BV) can occur de novo or can represent a morphologic transformation of MCL associated with aggressive clinical disease. Its cytologic appearance is very similar to that of lymphoblastic lymphoma (LBL) because of its characteristic nuclear features and high proliferative rate. To assess the usefulness of antibodies to cyclin D-1 (BCL-1/ PRAD-1), CD99 (12E7), CD34, and TdT in distinguishing between MCL-BV and LBL in formalin-fixed, paraffin-embedded tissue, we studied from the Stanford data base 10 cases originally diagnosed as B-lineage LBL, 5 MCL-BVs, 2 cases thought likely to represent MCL-BV, and 2 blastic lymphomas whose morphology and immunophenotype were indeterminate. Six (60%) of 10 LBLs stained with CD99, as opposed to none of 7 MCL-BVs. Four (40%) of 10 LBLs reacted with CD34, as compared with none of 7 MCL-BVs. Eight (89%) of nine LBLs were positive for TdT, but all of the four MCL-BVs tested were negative. In contrast, the anti-cyclin D-1 antibody stained the nuclei of all of the MCL-BVs and none of the LBLs tested. On the basis of our evaluation, the probable MCL-BV cases were considered to be definite MCL-BV. Of the indeterminate cases, one was considered to be LBL, whereas we felt that the other represented MCL-BV. We conclude that staining formalin-fixed, paraffin-embedded, high-grade lymphomas with anti-cyclin D-1 antibody is useful in confirming the diagnosis of MCL-BV, whereas positive reactions with CD99, CD34, and particularly TdT are more characteristic of LBL.

In situ detection of PCR-amplified HIV-1 and EBV nucleic acids in hyperplastic lymph nodes and in AIDS-related lymphoma.

The purpose of this study was to determine the in situ distribution of PCR-amplified HIV-1 and EBV DNA in hyperplastic lymph nodes and in AIDS-related lymphomas. PCR amplified HIV-1 DNA was detected, on average, in about 30% and 20% of the CD4 and CD21 dendritic cells, respectively, in and around the expanded germinal centers of hyperplastic lymph nodes in seropositive, asymptomatic people. PCR-amplified EBV DNA was noted, on average, in about 20% of L26 B-cells. The amplified HIV-1 DNA was noted in rare non-neoplastic cells in five AIDS-related lymphomas; the other three cases were negative for the viral DNA. Amplified EBV DNA was detected in five of eight lymphomas but in only three of these tissues did the viral DNA localize to the malignant cells. We conclude that although many cells in hyperplastic lymph nodes from people with early HIV-1 infection contain HIV-1 and EBV DNA, these viruses are of ten absent in the malignant cells of AIDS-related lymphoma. This suggests that although infection by these viruses and the concomitant lymphoid hyperplasia may predispose to lymphoma, the viruses are not required for maintenance of the malignant phenotype.

Esquemas de quimioterapia de linfomas / Scheme of chemoterapy lynphoma

Se presenta este tema en el 1er. Simposium Internacional de Linfomas, considerando de interés que es de gran ayuda tener a la mano un formato de bolsillo con la actualización de los esquemas de la quimioterapia tanto para la enfermedad de Hodkin como para los linfomas no-hodgkin

Epitopes of cartilage core proteins and GAG pattern in human non-Hodgkin lymphoma xenografts.

Glycosaminoglycan and core protein components of proteoglycans (PGs) have been studied in three human non-Hodgkin lymphoma xenografts of B cell origin. Lymphomas showed similar GAG content, but different composition of GAG subtypes. This variability was accompanied by an individual capacity to adhere to extracellular matrix elements. The core proteins identified by monoclonal antibodies raised against human cartilage chondroitin sulfate PG were also distinctly expressed and released. These proteins shared by different cell types may have biological significance.

VIP receptors in human SUP-T1 lymphoblasts.

We characterized a new type of vasoactive intestinal peptide (VIP) receptors in the CD4+ Stanford University Pediatric (SUP)-T1 lymphoma cell line, by comparing receptor occupancy [in the presence of (125I)helodermin and (125I)(acetyl-His1)VIP] and adenylate cyclase activation (in the presence of GTP). The order of potency of peptides on both parameters was: helodermin greater than (acetyl-His1)VIP greater than (Phe1)VIP = VIP greater than PHI while secretin was ineffective. In membranes, when Gs was permanently activated by Gpp(NH)p or by ADP-ribosylation (after pretreating intact lymphoblasts for 2 h with cholera toxin), there resulted a variably increased affinity of receptors for VIP-like peptides, suggesting reduced receptor selectivity. Preexposing intact lymphoblasts to the same peptides induced, within 5 min, homologous desensitization (i.e. reduced binding capacity and even more so impaired capability to activate adenylate cyclase), whose extent correlated with the Kd of each peptide at time 0. After prolonged (16 h) exposure to 30 nM VIP that resulted in marked (75%) downregulation, 60% of the adenylate cyclase responsiveness could recover within 30-120 min even in the presence of cycloheximide, but further resensitization was cycloheximide-sensitive. To conclude, VIP receptors coupled to adenylate cyclase showed distinct specificity in human SUP-T1 lymphoblasts. Their specificity decreased when Gs was permanently activated. In intact cells exposed to VIP-like peptides, the receptors were rapidly desensitized, then down-regulated, the resensitization mechanism being not immediately inhibited by cycloheximide.