Biomedical subjects

D P LeBrun

Publications and source records attributed to D P LeBrun.

22 records · Page 2Linked to original sources

PubMed1992

Follicular lymphomas of the gastrointestinal tract. Pathologic features in 31 cases and bcl-2 oncogenic protein expression.

The gastrointestinal tract is the most common site for extranodal lymphomas, but follicular lymphomas involving the gut are rare. To study their pathologic features and bcl-2 expression, 31 follicular lymphomas of the GI tract were reviewed and unstained paraffin sections from 24 of the cases were immunohistochemically stained using a monoclonal antibody for the peptide product of the proto-oncogene bcl-2. The most common site of lymphoma involvement was the small intestine, especially the terminal ileum. Gastric lymphomas tended to present clinically with symptomatic ulcers and small intestinal lesions presented with obstruction. Five cases involving the terminal ileum or colon had a gross appearance of multitudinous mucosal polyps and were considered to represent examples of "multiple lymphomatous polyposis." Enhanced expression of the bcl-2 oncogenic protein was detectable in lymphoma cells in 75% of cases and at lower levels in normal lymphoid cells in most cases. Small cleaved or mixed cell lymphomas were more likely to show enhanced expression than were large cell cases. Reactive germinal centers showed no bcl-2 staining. It is concluded that follicular GI lymphomas are associated with distinctive pathological features. In their tendency to express bcl-2, these neoplasms resemble their lymph node-based counterparts. Immunohistochemical staining for enhanced bcl-2 expression is of potential diagnostic utility in distinguishing between follicular lymphoma and follicular lymphoid hyperplasia in the gastrointestinal tract. The relevance of the results to lymphoma of mucosa-associated lymphoid tissue (MALT) is discussed.

Female↗

PubMed1991

Essential thrombocythemia with the Philadelphia chromosome and BCR-ABL gene rearrangement. An entity distinct from chronic myeloid leukemia and Philadelphia chromosome-negative essential thrombocythemia.

A 64-year-old woman presented with a platelet count of 3,225 x 10(9)/L. Bone marrow morphology showed massive megakaryocytic hyperplasia; cytogenetic studies showed the presence of the Philadelphia chromosome (Ph). The presence of a rearrangement involving the major breakpoint cluster region (mbcr) on chromosome 22 was confirmed by Southern blotting techniques. A diagnosis of Ph positive essential thrombocythemia (ET) was made. Such cases constitute less than 5% of patients with ET and it has been proposed that they be considered examples of chronic myelogenous leukemia (CML) because of a shared propensity to progress to blast crisis. An argument is presented for retaining Ph positive ET as an entity separate from Ph negative ET and Ph positive CML.

Blotting, Southern↗

PubMed1991

Fibrolamellar carcinoma of the liver in a patient with Fanconi anemia.

A 9-year-old boy with Fanconi anemia treated with oxymethalone, a synthetic androgen, died of intracerebral hemorrhage. At autopsy, the liver contained several adenomas and a large fibrolamellar hepatocellular carcinoma, as well as phlebectatic peliosis hepatis. The 11 previously reported cases of hepatocellular carcinoma in Fanconi anemia were not, apparently, of the fibrolamellar type, which has a better prognosis, occurs in children of both sexes, and generally is not associated with cirrhosis. The malignant potential of primary liver tumors associated with Fanconi anemia as well as the nature of their relationship to Fanconi anemia and to anabolic steroid therapy is discussed.

Carcinoma, Hepatocellular↗

PubMed1991

Growth fraction estimation of malignant lymphomas in formalin-fixed paraffin-embedded tissue using anti-PCNA/Cyclin 19A2. Correlation with Ki-67 labeling.

The immunohistochemical detection of PCNA/Cyclin, a nuclear protein associated with cell proliferation, represents a potentially useful tool for the study of tumor proliferative activity. Previous studies investigating the reactivity of anti-PCNA/Cyclin monoclonal antibody 19A2 have not clearly defined the population of proliferating cells with which 19A2 reacts in tissue sections. The authors describe a method for detection of PCNA/Cyclin in formalin-fixed, paraffin-embedded tissue using a routine biotin-streptavidin immunohistochemical system that employs an anti-IgM, mu-chain-specific second-stage antibody. The authors used this method to study the proliferative activity of 24 malignant lymphomas, consisting of 12 low-grade lymphomas (LGLs) and 12 intermediate-grade lymphomas (IGLs), and five reactive tonsils. 19A2 data was compared with Ki-67 labeling in frozen sections in the same group of cases. 19A2 provided easily detectable nuclear staining of proliferating cells with reactive cells demonstrating varying intensity of staining, this latter finding most likely due to the varying nuclear concentration of PCNA/Cyclin protein during the cell cycle. In tonsils, 19A2 reacted with germinal center cells and basal keratinocytes. In the malignant lymphomas, there was good correlation between 19A2 and Ki-67 data (r = 0.90, P less than 0.001). The subgroup of LGLs showed a mean PCNA/Cyclin of 26% and a mean Ki-67 of 28%. In the subgroup of IGLs, mean PCNA/Cyclin = 54% and mean Ki-67 = 59%. These results indicate that 19A2 detects a fraction of proliferating cells that is similar to that detected by Ki-67, ie, the growth fraction, and that 19A2 is a reliable marker of proliferative activity in uniformly handled, formalin-fixed, paraffin-embedded tissue.

Antibodies↗