Karen DeSombre

Association of Polymorphisms in the Apolipoprotein E Region with Susceptibility to and Progression of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system, with a complex etiology that includes a strong genetic component. The contribution of the major histocompatibility complex (MHC) has been established in numerous genetic linkage and association studies. In addition to the MHC, the chromosome 19q13 region surrounding the apolipoprotein E (APOE) gene has shown consistent evidence of involvement in MS when family-based analyses were conducted. Furthermore, several clinical reports have suggested that the APOE-4 allele may be associated with more-severe disease and faster progression of disability. To thoroughly examine the role of APOE in MS, we genotyped its functional alleles, as well as seven single-nucleotide polymorphisms (SNPs) located primarily within 13 kb of APOE, in a data set of 398 families. Using family-based association analysis, we found statistically significant evidence that an SNP haplotype near APOE is associated with MS susceptibility (P=.005). An analysis of disease progression in 614 patients with MS from 379 families indicated that APOE-4 carriers are more likely to be affected with severe disease (P=.03), whereas a higher proportion of APOE-2 carriers exhibit a mild disease course (P=.02).

Serum levels of HER‐2 neu (C‐erbB‐2) correlate with overexpression of p185neu in human ovarian cancer

Background. The HER‐2 neu (c‐erbB‐2) oncogene product p185neu is expressed by most ovarian cancers and overexpressed in approximately 30%.

Relative cytotoxic activity of immunotoxins reactive with different epitopes on the extracellular domain of the c-erbB-2 (HER-2/neu) gene product p185

Different epitopes on the extracellular domain of the HER‐2 receptor can serve as distinct targets for immunotoxins. To determine the optimal epitope target for immunotoxin therapy, 7 anti‐HER‐2 ricin A chain murine monoclonal immunotoxins, each reactive with different epitopes of HER‐2 receptor, were tested for cytotoxic activity. The immunotoxins produced 1.2–4.6 logs of cytotoxicity in limiting dilution clonogenic assays with 2 breast cancer cell lines that overexpressed HER‐2. Cytotoxicity did not correlate with immunoglobulin isotype, binding affinity, relative position of epitopes or internalization of the anti‐HER‐2 immunotoxins. Interestingly, the most and least effective immunotoxins bound to epitopes in very close proximity. Competitive binding assays with unconjugated antibodies have previously indicated that our antibodies recognized epitopes that are arranged in a linear array. To orient this relative epitope map, deletions were prepared in the HER‐2/neu gene and these mutant constructs were expressed in NIH3T3 cells. Epitope expression was determined by antibody binding and radioimmunoassay. Epitopes targeted by the PB3, 454C11 and NB3 antibodies are localized N‐terminal to the epitopes recognized by ID5, BD5, 741F8 and 520C9 antibodies. The 2 non‐conformational epitopes PB3 and NB3 were localized to regions corresponding to amino acides 78–242 of the p185HER‐2 protein. Int. J. Cancer 82:525–531, 1999.

OVX1 radioimmunoassay complements CA-125 for predicting the presence of residual ovarian carcinoma at second-look surgical surveillance procedures

PURPOSE At second-look surgical surveillance procedures, normal CA-125 levels can be associated with persistent disease in 50% to 60% of patients. A novel radioimmunoassay (RIA) has been evaluated for the ability to identify patients with persistent disease who have normal levels of CA-125. MATERIALS AND METHODS The OVX1 double-determinant assay used a murine monoclonal antibody to detect an epitope on a high-molecular weight mucin-like glycoprotein. RESULTS Apparently healthy individuals had serum OVX1 levels of 2.23 +/- 2.48 U/mL (mean +/- SD). Elevated serum OVX1 levels (> 7.2 U/mL) were found in 5% of 184 normal individuals and in 70% of 93 epithelial ovarian cancer patients with clinically evident disease. Among sera from these ovarian cancer patients, OVX1 was elevated in 68% of 76 samples with CA-125 levels more than 35 U/mL and in 76% of 17 samples with CA-125 levels less than 35 U/mL. In serum samples obtained at the time of positive second-look laparotomy, 59% of 41 patients with CA-125 levels less than 35 U/mL had elevated OVX1 antigen levels, whereas 41% of 22 patients with CA-125 levels more than 35 U/mL had elevated serum OVX1 levels. In patients with negative second-look laparotomies, false-positive results were eliminated by increasing the threshold of OVX1 to 10.5 U/mL. At this level, 32% of 41 patients with positive second-look operations had an elevated OVX1 level, despite a normal CA-125 level. When used in combination, CA-125 (> 35 U/mL) and OVX1 (> 10.5 U/mL) detected persistent disease in 56% of 63 patients with positive surveillance procedures, compared with 35% when CA-125 was used alone (P < .05). CONCLUSION An elevated OVX1 level can alert oncologists to the possibility that ovarian cancer has persisted, despite the return of CA-125 to a normal range.

Ex vivo expansion of bone marrow from breast cancer patients: reduction in tumor cell content through passive purging

High-dose chemotherapy (HDC) with hematopoietic support appears promising in the treatment of breast cancer, although reinfusion of contaminating tumor cells may contribute to disease relapse. Ex vivo expansion may reduce tumor cell content through use of a small inoculum volume and by passive purging during culture. We assessed the ex vivo expansion potential of tumor cell positive bone marrow (BM) from breast cancer patients and the effect of ex vivo expansion on tumor cell content. Cryopreserved/thawed mononuclear cell (C/T MNC) BM harvests with known tumor cell contamination (n = 7) were assessed for tumor cells pre- and post-expansion using immunocytochemical (ICC) staining. Pre-expansion inoculum samples contained a range of 6–2128 tumor cells per 5.0 × 106 nucleated cells. Ex vivo expansion resulted in fold expansions of 6.67 and 11.37 for total cells and CFU-GM, respectively. Tumor cells were undetectable in four of the seven post-expansion samples and were reduced in the remaining three samples. The data demonstrate passive purging of breast cancer cells during ex vivo expansion, with hematopoietic progenitor cell expansion comparable to that of normal BM. Reduction in tumor cell number contained in the small volume culture inoculum combined with passive purging during the ex vivo expansion process suggest a potential 2–4+ log reduction in tumor cell content in the reinfused cell product.