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Karen Lu

Publications and source records attributed to Karen Lu.

11 recordsLinked to original sources

Association between clinical characteristics and risk-reduction interventions in women who underwent BRCA1 and BRCA2 testing: a single-institution study.

BACKGROUND: Women who are at increased risk for breast and ovarian cancers, especially BRCA1 and BRCA2 mutation carriers, face a myriad of risk-reduction options, including increased surveillance, chemoprevention, prophylactic oophorectomy, and prophylactic mastectomy. However, little is known about which clinical, demographic, or cancer-related factors are associated with risk-reduction interventions. METHODS: The authors conducted a retrospective review of records for 554 women who had undergone testing at The University of Texas M. D. Anderson Cancer Center between 2000 and 2006 for deleterious BRCA1 and BRCA2 gene mutations. Data were collected on the risk-reduction interventions these women adopted after they underwent genetic testing. These data were tested for associations with demographic and clinical characteristics. RESULTS: Among the 554 women who underwent genetic testing for BRCA mutation, 78 were found to have a deleterious mutation in the BRCA1 gene, and 54 had a mutation in the BRCA 2 gene. Of the 554 women, 85 underwent prophylactic mastectomy, 30 prophylactic oophorectomy, and 52 both surgeries; 387 women opted for surveillance. Women who had BRCA mutations, a history of breast cancer or ductal carcinoma in situ (DCIS), or previous breast biopsies were more likely to have prophylactic surgery. Women with a family history of ovarian cancer were more likely to undergo prophylactic oophorectomy. Women with a personal history of ovarian cancer or advanced breast cancer were more likely to undergo surveillance only. Women with breast cancer who had had a total mastectomy as part of their prior breast cancer treatment underwent prophylactic mastectomy more frequently than women who either had breast-conserving surgery or no history of breast cancer. In multivariate analysis, only positive BRCA mutation carrier status was associated with having had prophylactic surgery. In addition, breast cancer history was significantly associated with prophylactic mastectomy. CONCLUSIONS: Women who were BRCA carriers, women who had a history of breast cancer, DCIS, or breast biopsy, or had a family history of ovarian cancer were more likely to have undergone surgery for cancer risk reduction. Women with ovarian cancer or advanced breast cancer were more likely to have undergone surveillance.

BRCA1 Protein↗

Diagnostic markers of ovarian cancer by high-throughput antigen cloning and detection on arrays.

A noninvasive screening test would significantly facilitate early detection of epithelial ovarian cancer. This study used a combination of high-throughput selection and array-based serologic detection of many antigens indicative of the presence of cancer, thereby using the immune system as a biosensor. This high-throughput selection involved biopanning of an ovarian cancer phage display library using serum immunoglobulins from an ovarian cancer patient as bait. Protein macroarrays containing 480 of these selected antigen clones revealed 65 clones that interacted with immunoglobulins in sera from 32 ovarian cancer patients but not with sera from 25 healthy women or 14 patients having other benign or malignant gynecologic diseases. Sequence analysis data of these 65 clones revealed 62 different antigens. Among the markers, we identified some known antigens, including RCAS1, signal recognition protein-19, AHNAK-related sequence, nuclear autoantogenic sperm protein, Nijmegen breakage syndrome 1 (Nibrin), ribosomal protein L4, Homo sapiens KIAA0419 gene product, eukaryotic initiation factor 5A, and casein kinase II, as well as many previously uncharacterized antigenic gene products. Using these 65 antigens on protein microarrays, we trained neural networks on two-color fluorescent detection of serum IgG binding and found an average sensitivity and specificity of 55% and 98%, respectively. In addition, the top 6 of the most specific clones resulted in an average sensitivity and specificity of 32% and 94%, respectively. This global approach to antigenic profiling, epitomics, has applications to cancer and autoimmune diseases for diagnostic and therapeutic studies. Further work with larger panels of antigens should provide a comprehensive set of markers with sufficient sensitivity and specificity suitable for clinical testing in high-risk populations.

Antigens, Neoplasm↗

An HSP90-mimic peptide revealed by fingerprinting the pool of antibodies from ovarian cancer patients.

To gain insight into the mechanisms of molecular recognition and humoral immune response in ovarian cancer, we used fingerprinting, a phage display-based combinatorial selection to isolate peptide ligands to tumor-related antibodies present in ascites from patients with advanced disease. First, we have isolated a consensus motif (sequence CVPELGHEC) in 86% of the peptides screened; this enriched motif was selected from a total of 10(8)-10(9) unique random sequences present in the library. Next, we identified the heat-shock protein 90 kDa (HSP90) as the native antigen mimicked by the motif. Finally, we evaluated the expression of HSP90 and the presence of antibodies against the HSP90-mimic peptide in a large panel of ovarian cancer patients and controls. In tissue microarrays, we show that the expression of HSP90 is ubiquitous. However, the corresponding humoral immune response against HSP90 is restricted to a subset of patients with stage IV disease. Together, these results show that screening humoral response can identify tumor antigens that may serve as molecular targets in ovarian cancer. Recognition of such relevant proteins in the immunobiology of malignant tumors may lead to the development of therapies

Amino Acid Motifs↗

Grading ovarian serous carcinoma using a two-tier system.

In this study, we evaluate a two-tier system for grading ovarian serous carcinoma. This system is based primarily on the assessment of nuclear atypia with the mitotic rate used as a secondary feature. The study included 50 cases of low-grade ovarian serous carcinoma and 50 cases of high-grade ovarian serous carcinoma retrieved from the files of the Department of Pathology at the University of Texas M. D. Anderson Cancer Center from a 28-year period. Cases assigned to the low-grade category were characterized by the presence of mild to moderate nuclear atypia. As a secondary feature, they tended to show up to 12 mitoses per 10 high power fields (HPFs), whereas those in the high-grade category had marked nuclear atypia and as a secondary feature more than 12 mitoses per 10 HPFs. For comparison, the tumors were also graded using the Shimizu/Silverberg and the FIGO grading systems. Patients in the low-grade ovarian serous carcinoma group ranged in age from 19 to 75 years (mean 41.7 years) while patients in the high-grade ovarian serous carcinoma group ranged in age from 27 to 76 years (mean 55 years). All of the cases except one were advanced FIGO stage. Using the Shimizu/Silverberg system, the low-grade ovarian serous carcinoma cases were distributed as follows: grade 1, 47 cases; grade 2, 3 cases. Using the FIGO grading system, 35 cases were grade 1 and 15 cases were grade 2. Regarding the high-grade ovarian serous carcinoma group using the Shimizu/Silverberg system, 14 of the cases were grade 2 and 36 cases were grade 3. Using the FIGO grading system, 1 case was grade 1, 38 cases were grade 2, and 11 cases were grade 3. Most of the patients in both groups were treated with total abdominal hysterectomy and bilateral salpingo-oophorectomy and also received cisplatinum-based chemotherapy. On follow-up, 37 patients in the low-grade ovarian serous carcinoma group had died of disease at a median 4.2 years after diagnosis compared with 46 patients in the high-grade ovarian serous carcinoma group who died of disease at a median of 1.7 years. Eight patients in the low-grade ovarian serous carcinoma group and 4 patients in the high-grade ovarian serous carcinoma group were alive with disease at median follow-ups of 4.3 and 3.85 years, respectively. Four patients with low-grade serous carcinoma were alive without evidence of disease after a follow-up that ranged from 4.4 to 22.6 years (median 6.85 years), and one died of other causes 14 years after the diagnosis of her ovarian tumor. On multivariate analysis, residual tumor and tumor grade based on the M. D. Anderson two-tier system for grading ovarian serous carcinoma were found to be significant independent prognostic factors (P = 0.003 and 0.04, respectively). Of interest, 60% of the low-grade ovarian serous carcinomas in this study were associated with a serous neoplasm of low malignant potential, whereas this association was present in only 2% of the high-grade ovarian serous carcinomas. This finding could reflect a difference in the pathogenesis of ovarian serous carcinomas of different grades. In summary, there is usually a good correlation between the two-tier grading system herein presented and the Shimizu/Silverberg and the FIGO grading systems. Because this system is based on defined criteria that are easy to follow and because it involves only two diagnostic categories, it should provide better reproducibility in the grading of ovarian serous carcinoma. However, additional studies are required to validate these statements.

Adult↗

Antimicrobial resistance gene delivery in animal feeds.

Avoparcin, a glycopeptide antimicrobial agent related to vancomycin, has been used extensively as a growth promoter in animal feeds for more than 2 decades, and evidence has shown that such use contributed to the development of vancomycin-resistant enterococci. A cluster that includes three genes, vanH, vanA, and vanX, is required for high-level resistance to glycopeptides. In the vancomycin producer Amycolatopsis orientalis C329.2, homologs of these genes are present, suggesting an origin for the cluster. We found substantial bacterial DNA contamination in animal feed-grade avoparcin. Furthermore, nucleotide sequences related to the cluster vanHAX are present in this DNA, suggesting that the prolonged use of avoparcin in agriculture led to the uptake of glycopeptide resistance genes by animal commensal bacteria, which were subsequently transferred to humans.

Animal Feed↗

Role of decreased levels of lipid phosphate phosphatase-1 in accumulation of lysophosphatidic acid in ovarian cancer.

The levels of lysophosphatidic acid (LPA) are consistently elevated in the ascites of ovarian cancer patients, suggesting that ovarian cancer cells are exposed to an LPA replete environment. LPA stimulates cell proliferation, cell survival, resistance to cisplatin, production and activation of proteases, invasiveness and production of the neovascularizing factors, vascular endothelial growth factor, and interleukin 8. Although ovarian cancer cells can produce LPA, this may not be the major reason for altered LPA levels in ascites. We have demonstrated that the major mechanism of degradation of LPA by ovarian cancer cells is through a lipid phosphate phosphatase (LPP)-like activity. We demonstrate herein that LPP-1 mRNA is decreased in the majority of ovarian cancers. This is recapitulated in ovarian cancer cell lines, where LPP-1 RNA levels are lower than those in normal ovarian epithelium and immortalized ovarian epithelial cells. Introduction of LPP-1 into ovarian cancer cell lines results in increased LPA hydrolysis, which is associated with a marked inhibition of cell proliferation and colony-forming activity and a marked increase in apoptosis. Thus, the LPA-rich environment of the ovarian cancer cell in vivo and the subsequent effects of cellular pathophysiology may be a consequence of both increased LPA production and decreased LPA metabolism by ovarian cancer cells.

Cell Division↗

Molecular determinants of tumor differentiation in papillary serous ovarian carcinoma.

In epithelial ovarian cancer, tumor grade is an independent prognosticator whose molecular determinants remain unknown. We investigated patterns of gene expression in well- and poorly differentiated serous papillary ovarian and peritoneal carcinomas with cDNA microarrays. A 6500-feature cDNA microarray was used for comparison of the molecular profiles of eight grade III and four grade I stage III serous papillary adenocarcinomas. With a modified F-test in conjunction with random permutations, 99 genes whose expression was significantly different between grade I and grade III tumors were identified (P < 0.01). A disproportionate number of these differentially expressed genes were located on the chromosomal regions 20q13 and all exhibited higher expression in grade III tumors. Interphase fluorescent in situ hybridization demonstrated 20q13 amplification in two of the four grade III and none of the three grade I tumors available for evaluation. Several centrosome-related genes also showed higher expression in grade III tumors. We propose a model in which tumor differentiation is inversely correlated with the overexpression of several oncogenes located on 20q13, a common amplicon in ovarian and numerous other cancers. Dysregulation of centrosome function is one potential mechanistic link between genetic/epigenetic changes and the poorly differentiated phenotype in ovarian cancer.

Biomarkers, Tumor↗

Unexpected endometrial cancer at prophylactic hysterectomy in a woman with hereditary nonpolyposis colon cancer.

BACKGROUND: Hereditary nonpolyposis colon cancer is associated with a 40-60% lifetime risk of endometrial cancer. Prophylactic hysterectomy is a reasonable management strategy for women who have completed childbearing. We report a case of a woman with hereditary nonpolyposis colon cancer who was found to have an unexpected endometrial cancer at prophylactic hysterectomy. CASE: A woman with hereditary nonpolyposis colon cancer underwent a laparoscopically assisted vaginal hysterectomy and bilateral salpingo-oophorectomy for prophylaxis against endometrial cancer. No unusual intraoperative findings were noted. Pathologic examination revealed a mixed clear cell and endometrioid endometrial carcinoma invading into the myometrium and cervix. The patient underwent a subsequent staging laparotomy, in which no additional disease was found. CONCLUSION: Patients with known hereditary nonpolyposis colon cancer undergoing prophylactic hysterectomy are at risk for having occult endometrial cancer. Gynecologists should consider preoperative endometrial biopsy and intraoperative assessment of the endometrium in these high-risk women.

Carcinoma, Endometrioid↗

Response and survival in patients with progressive or recurrent serous ovarian tumors of low malignant potential.

OBJECTIVE: To evaluate the response to therapy and survival of patients with progressive or recurrent serous ovarian tumors of low malignant potential. METHODS: Fifty-three patients with progressive or recurrent serous ovarian tumors of low malignant potential were identified. Response was assessed and progression-free and overall survival were analyzed. The influence of clinicopathologic factors on survival was determined. RESULTS: In 49 patients with known histology of progression or recurrence, 36 (73%) had low-grade serous carcinoma, and 13 (27%) had serous ovarian tumors of low malignant potential. Forty-five patients received nonsurgical therapy and had an evaluable response. There were six (13%) patients with a complete response and six (13%) patients with a partial response. The median time to first progression or recurrence was 5.6 years. Median survival from diagnosis of first recurrence was 7.7 years. Median survival from initial diagnosis was 21 years. Nineteen (36%) patients are dead of tumor. Patients who recurred with low-grade serous carcinoma were more likely to die of tumor than those with serous ovarian tumors of low malignant potential (47% versus 0%, P =.045). Optimal cytoreduction was associated with improved survival (P =.007). CONCLUSION: Patients with progressive or recurrent serous ovarian tumors of low malignant potential have a long interval from diagnosis to progression and from progression to death, resulting in extended overall survival. Recurrence as low-grade serous carcinoma and failure to achieve optimal secondary cytoreduction were adverse prognostic factors. There were few responses to nonsurgical therapy.

Adult↗

Cultivation-dependent characterization of bacterial diversity from British Columbia forest soils subjected to disturbance.

Bacteria from forest surface organic matter and mineral soil horizons were cultivated using four methods and characterized by fatty acid methyl ester (FAME) analysis. Soil samples from a British Columbia Ministry of Forests Long-Term Soil Productivity (LTSP) installation were collected during winter and summer from two disturbance treatments (whole-tree harvesting with no soil compaction (plot N) and whole-tree harvesting plus complete surface organic matter removal with heavy soil compaction (plot S)) and from an unlogged reference plot (REF). Seventy-five percent of 1795 bacterial isolates were affiliated with 42 genera representing beta- and gamma-Proteobacteria, Actinobacteria, the Bacillus/Clostridium group, and the Cytophaga-Flexibacter-Bacteroides group. Approximately half of the culture collection represented genetic diversity confined to four bacterial genera: Pseudomonas, Bacillus, Paenibacillus, and Arthrobacter. A significantly higher proportion of bacterial isolates belonging to Actinobacteria, and the member genus Arthrobacter, were isolated from plot S soil samples compared with soil samples from plots N and REF. Twenty-five percent of bacterial isolates were not conclusively identified to genus with FAME analysis. Sherlock Tracker cluster analysis and partial 16S rRNA gene sequence analysis enabled classification of a subset of these isolates.

Bacteria↗