Optimal detection of micrometastases in sentinel lymph node of breast cancer: CBCSG-001 trial

Abstract #1011

Background: Although sentinel lymph node biopsy (SLNB) has become the method of choice for axillary staging, the extent of the pathological examination (HE or IHC, the number or intervals of sections) described in the literature differed considerably between studies, particularly for the detection of micrometastases (MMs). As one of the second objectives of the CBCSG–001 trial (China multicenter study of sentinel node biopsy substituting axillary node dissection), our aim was to evaluate the optimal methods and intervals for the detection of SLN macrometastases, MMs and isolated tumor cells (ITCs).
 Material and Methods: Two hundred and forty-five continuous breast cancer patients with 569 SLNs identified “negative” with standard HE stain carried on initial 4 levels were retrospectively analyzed. All SLNs were step sectioned (SS) at 100µm interval, and for each level both HE and IHC with AE1/AE3 were performed. Then HE and IHC detection rates were analyzed at 100-, 200-, 300-, 400-, and 500µm intervals for the detection of macrometastases, MMs and ITCs.
 Results: In 245 cases with original SLN negative cases, 36 (14.7%), 49 (20.0%) and 49 (20.0%) cases were found to had metastases with SS HE, SS IHC, and SS HE+IHC, respectively (SS IHC/ SS HE+IHC vs. SS HE, p>0.05). In all the 5741 sections, metastases were found in 180 sections (3.1%) by SS HE, 307 (5.4%) by SS IHC, and 322 (5.6%) by SS HE+IHC (p=0.000). The metastases included macrometastases 12.2%, MMs 61.2%, and ITC 26.5%. The detection rates of MMs were 7.8%, 12.2%, and 12.2%, respectively (SS IHC/ SSHE+IHC vs. SS HE, p>0.05). The detection rates of ITCs were 4.5%, 5.3%, and 5.3%, respectively (p>0.05). The detection rates of metastases were significantly higher in patients with invasive lobular carcinoma (57.1%) than with invasive ductal carcinoma (16.7%, p=0.001), but no significant differences were found among different ages, tumor sizes, locations, grades, ER, PR, and HER-2 status (all p>0.05). The detection rates of metastases at 100-, 200-, 300-, 400-, and 500-µm intervals by SS HE were 14.7%, 13.5%, 11.4%, 8.6%, and 7.8%, respectively. No significant differences were found between 100- and 200-µm intervals (p=0.697), and between 100- and 300-µm (p=0.284), while p<0.05 between 100-µm and other intervals. The detection rates of metastases at 100-, 200-, 300-, 400-, and 500-µm intervals by SS HE+IHC were 20.0%, 18.8%, 18.0%, 16.3%, and 13.1%, respectively. No significant difference was found between 100- and 200-µm intervals (p=0.732), 100- and 300-µm (p=0.565), and between 100- and 400-µm (p=0.292), while p=0.041 between 100-µm and 500-µm.
 Conclusion: SS HE could significantly increase the detection rate of SLN metastasis compared to our routine 4 levels HE pathological examination. SS HE+IHC could further improve the detection of SLN metastases. The detection rates of metastases were significantly higher in patients with invasive lobular carcinoma than those with invasive ductal carcinoma. The optimal interval for the detection of micrometastases in SLN was 300-µm with SS HE, and 400-µm with SS HE+IHC.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1011.

Mechanotransducers in rat pulpal afferents

The hydrodynamic theory suggests that pain associated with stimulation of a sensitive tooth ultimately involves mechanotransduction as a consequence of fluid movement within exposed dentinal tubules. To determine whether putative mechanotransducers could underlie mechanotransduction in pulpal afferents, we used a single-cell PCR approach to screen retrogradely labeled pulpal afferents. The presence of mRNA encoding BNC-1, ASIC3, TRPV4, TRPA1, the alpha, beta, and gamma subunits of ENaC, and the two pore K+ channels (TREK1, TREK2) and TRAAK were screened in pulpal neurons from rats with and without pulpal inflammation. ASIC3, TRPA1, TREK1, and TREK2 were present in approximately 67%, 64%, 14%, and 10% of pulpal neurons, respectively. There was no detectable influence of inflammation on the proportion of neurons expressing these mechanotransducers. Given that the majority of pulpal afferents express ASIC3 and TRPA1, our results raise the possibility that these channels may be novel targets for the treatment of dentin sensitivity.

The influence of caecectomy on amino acid availability of three feedstuffs for ganders

1. Experiments were conducted to assess the influence of caecectomy on amino acid availability (AAA) of three feedstuffs for goose. 2. Nine caecectomised and 9 intact Yangzhou ganders, 24 weeks old, were used in these experiments. Fish meal, soybean meal and cottonseed meal were used as the sole source of protein. The endogenous amino acid (AA) losses were evaluated by a nitrogen (N)-free diet method. The influence of caecectomy on apparent amino acid availability (AAAA) in fish meal, soybean meal and cottonseed meal was assessed in experiment 1 and true amino acid availability (TAAA) of three protein diets was determined in experiment 2. 3. Results showed that, in the soybean meal and cottonseed meal, the AAAA and TAAA of most AA determined by the intact ganders were higher than in the caecectomised ganders; in the fish meal, the AAAA and TAAA of most AA determined by the intact ganders were lower than in the caecectomised ganders. 4. Results of the present study suggest that the effect of caecectomy on AAA in geese was dependent on the feedstuff assayed, and it was better to use caecectomised poultry for AAA assessment.

Gaseous ozone treatment inactivates Listeria innocua in vitro

AIMS

To investigate the effects of ozone on inactivation of Listeria innocua on solid media.

METHODS AND RESULTS

Suspensions of L. innocua ranging from 4.5 x 10(4 )- 6.4 x 10(4) CFU ml(-1) were inoculated onto potato dextrose agar (PDA, pH 5.6 and 6.8) and nutrient agar (NA, pH 6.0 and 6.8), then exposed to gaseous ozone. Variable factors included postinoculation standing time at 20 degrees C before exposure to ozone, ozone concentration, treatment duration and treatment temperature (5 or 20 degrees C). The interaction among ozone concentration, treatment duration, media and temperature in effecting changes in colony-forming units (CFU) was significant. The 100 nl l(-1) ozone treatment for 2 h reduced the microbial populations by 2-3 log CFU ml(-1). Cell viability decreased more rapidly on PDA than on NA. The average time to obtain a 2 log CFU ml(-1) reduction was 1.3 h at 20 degrees C and 2.5 h at 5 degrees C (P < 0.001).

CONCLUSIONS

Gaseous ozone effectively inactivates L. innocua at concentrations of 50 and 100 nl l(-1) during short exposure times at both 5 and 20 degrees C. The Gompretz model can be utilized for determining the response of L. innocua to ozone over time.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides useful information on ozone inactivating Listeria spp., which may be imposed on ensuring quality and safety of horticultural produce and food products.

Enhancement of therapeutic effectiveness by combining liposomal honokiol with cisplatin in ovarian carcinoma

Honokiol, a well-tolerated natural product, can inhibit the proliferation of cancer cells. But its water insolubility hampers its systemic administration for therapy of cancer. As a drug delivery system, the pegylated liposome (PEGL) can increase the water solubility and targeting of the drug. Honokiol has been successfully encapsulated by PEGL in our laboratory. We wondered whether the combination treatment with pegylated liposomal honokiol (H-PEGL) and cisplatin (DDP) could improve the antitumor efficacy in ovarian carcinoma. H-PEGL could introduce apoptosis of SKOV3 cells in vitro, which was quantified by flow cytometric analysis, and the cellular morphologic changes were determined by propidium iodide staining. In a human ovarian carcinoma mouse model, combination treatment with H-PEGL (0.4 mg/day for 30 days; intraperitoneal) and DDP (5 mg/kg on days 7, 11, 15, 19; intraperitoneal) acted synergistically to inhibit tumor growth by 91.48% without notable toxicity, but H-PEGL and DDP alone only inhibit tumor growth by 66.83% and 52.5% as compared to the NaCl solution control, respectively. Assessment of microvessel density and apoptosis index by CD31 and terminal deoxynucleotidyl transferase-mediated nick end labeling immunohistochemistry respectively suggested that the antitumor activity of H-PEGL is mediated by angiogenesis inhibition and introduction of apoptosis. Our results showed us a splendid prospect of the clinical application of combination treatment on patients suffering from ovarian cancer with H-PEGL and DDP.

PXR, CAR and HNF4alpha genotypes and their association with pharmacokinetics and pharmacodynamics of docetaxel and doxorubicin in Asian patients

Previously studied candidate genes have failed to account for inter-individual variability of docetaxel and doxorubicin disposition and effects. We genotyped the transcriptional regulators of CYP3A and ABCB1 in 101 breast cancer patients from 3 Asian ethnic groups, that is, Chinese, Malays and Indians, in correlation with the pharmacokinetics and pharmacodynamics of docetaxel and doxorubicin. While there was no ethnic difference in docetaxel and doxorubicin pharmacokinetics, ethnic difference in docetaxel- (ANOVA, P=0.001) and doxorubicin-induced (ANOVA, P=0.003) leukocyte suppression was observed, with Chinese and Indians experiencing greater degree of docetaxel-induced myelosuppression than Malays (Bonferroni, P=0.002, P=0.042), and Chinese experiencing greater degree of doxorubicin-induced myelosuppression than Malays and Indians (post hoc Bonferroni, P=0.024 and 0.025). Genotyping revealed both PXR and CAR to be well conserved; only a PXR 5'-untranslated region polymorphism (-24381A>C) and a silent CAR variant (Pro180Pro) were found at allele frequencies of 26 and 53%, respectively. Two non-synonymous variants were identified in HNF4alpha (Met49Val and Thr130Ile) at allele frequencies of 55 and 1%, respectively, with the Met49Val variant associated with slower neutrophil recovery in docetaxel-treated patients (ANOVA, P=0.046). Interactions were observed between HNF4alpha Met49Val and CAR Pro180Pro, with patients who were wild type for both variants experiencing least docetaxel-induced neutropenia (ANOVA, P=0.030). No other significant genotypic associations with pharmacokinetics or pharmacodynamics of either drug were found. The PXR-24381A>C variants were significantly more common in Indians compared to Chinese or Malays (32/18/21%, P=0.035) Inter-individual and inter-ethnic variations of docetaxel and doxorubicin pharmacokinetics or pharmacodynamics exist, but genotypic variability of the transcriptional regulators PAR, CAR and HNF4alpha cannot account for this variability.

The Effect of Herbal Medicine Baicalin on Pharmacokinetics of Rosuvastatin, Substrate of Organic Anion-transporting Polypeptide 1B1

The aim of this study was to explore potential herb-drug interaction between baicalin and rosuvastatin, a typical substrate for organic anion-transporting polypeptide 1B1 (OATP1B1) related to different OATP1B1 haplotype groups. Eighteen unrelated healthy volunteers who were CYP2C9*1/*1 with different OATP1B1 haplotypes (six OATP1B1*1b/*1b, six OATP1B1*1b/*15, and six OATP1B1*15/*15) were selected to participate in this study. Rosuvastatin (20 mg orally) pharmacokinetics after coadministration of placebo and 50-mg baicalin tablets (three times daily orally for 14 days) were measured for up to 72 h by liquid chromatography-mass spectrometry in a two-phase randomized crossover study. After baicalin treatment, the area under the plasma concentration-time curve (AUC)(0-72) and AUC(0-infinity) of rosuvastatin decreased by 47.0+/-11.0% (P=0.001) and 41.9+/-7.19% (P=0.001) in OATP1B1*1b/*1b, 21.0+/-20.6% (P=0.035) and 23.9+/-8.66% (P=0.004) in OATP1B1*1b/*15, and 9.20+/-11.6% (P=0.077) and 1.76+/-4.89% (P=0.36) in OATP1B1*15/*15, respectively. Moreover, decreases of both AUC(0-72) and AUC(0-infinity) of rosuvastatin among different haplotype groups were significantly different (P=0.002 and <0.001). Baicalin reduces plasma concentrations of rosuvastatin in an OATP1B1 haplotype-dependent manner.

Genetic variants in human carbonyl reductase 3 (CBR3) and their influence on doxorubicin pharmacokinetics in Asian breast cancer patients

2505

Background: Human carbonyl reductase 3 (CBR3) is one of the main metabolizing enzymes to extensively reduce doxorubicin to its major active metabolite, doxorubicinol in normal and tumor tissues. Recently, the CBR3 958G>A (V244M) genetic variant has been described to alter function in vitro. We postulate that CBR3 genetic variants could contribute to the inter-individual variability of doxorubicin pharmacokinetics in breast cancer patients. Methods: We studied 101 female breast cancer patients (66 Chinese, 26 Malay, 7 Indian and 2 of other ethnic origins) who were treated with doxorubicin at 75mg/m2 every 3 weeks. Comprehensive sequencing of the 3 exons of CBR3, including the splice-site junctions was performed. Plasma concentrations of doxorubicin and doxorubicinol were analyzed during the first doxorubicin cycle. Results: Five CBR3 coding region variants (239G>A, 483C>T, 507C>T, 598G>A and 958G>A) were detected, of which 239G>A, 598G>A and 958G>A were non-synonymous. 598G>A was novel, and was found in 1 Malay patient who was heterozygous. The genotype distributions of 239G>A and 958G>A were 36%/30%/34%, and 40%/36%/24% respectively for GG/AG/AA. The 239GG variant was associated with significantly higher AUC of doxorubicinol and AUC ratio of doxorubicinol to doxorubicin than the AG and AA variants (AUC of doxorubicinol 2.18±1.37ug/ml*h (GG) vs 2.04±2.11ug/ml*h (AG), p=0.05, and 1.55±0.61ug/ml*h (AA), p=0.004; AUC ratio of doxorubicinol to doxorubicin 1.90±1.29 (GG) vs 1.72±1.34 (AG), p=0.025, and 1.45±0.67 (AA), p=0.006). Patients with the 958AA variant had significantly higher AUC of doxorubicinol than those with the 958GG variant (2.29±1.60ug/ml*h vs 1.56±0.60ug/ml*h, p=0.009). The 239GG variant was more common in our population than in Caucasians (36% vs 20%. p=0.027), while the 958AA variant was more common than reported in Caucasians (24% vs 8%, p=0.014) and Japanese (24% vs 7%, p=0.016). Conclusions: CBR3 genetic variants may influence the pharmacokinetics of doxorubicin and its major metabolite doxorubicinol. Inter-ethnic differences in frequencies of CBR3 genetic variants exist and may account for differences in pharmacokinetics and pharmacodynamics of doxorubicin between different populations.

No significant financial relationships to disclose.

AGS and other tissue culture cells can unknowingly be persistently infected with PIV5; a virus that blocks interferon signalling by degrading STAT1

Whilst screening various cell lines for their ability to respond to interferon (IFN), we noted that in comparison to other tissue culture cells AGS tumour cells, which are widely used in biomedical research, had very low levels of STAT1. Subsequent analysis showed that the reason for this is that AGS cells are persistently infected with parainfluenza virus type 5 (PIV5; formally known as SV5), a virus that blocks the interferon (IFN) response by targeting STAT1 for proteasome-mediated degradation. Virus protein expression in AGS is altered in comparison to the normal pattern of virus protein synthesis observed in acutely infected cells, suggesting that the AGS virus is defective. We discuss the relevance of these results in terms of the need to screen cell lines for persistent virus infections that can alter cellular functions.

Recurrent spontaneous abortions patients have more −14 bp/+14 bp heterozygotes in the 3′UT region of the HLA-G gene in a Chinese Han population

Although human leukocyte antigen (HLA)-G gene polymorphism is low, it may influence levels of protein expression and, in some cases, has been associated with pregnancy diseases. Apart from the 23 HLA-G alleles, including a null allele known as HLA-G*0105N, a 14-bp deletion or insertion in the 3'UT region also contributes to the HLA-G gene polymorphism. In order to discover any correlation between the 14-bp deletion polymorphism and pregnancy diseases, we isolated the genomic DNA from 24 recurrent spontaneous abortions (RSA) patients and 88 normal fertile control individuals using the salted out method. Exon-8 of HLA-G gene of the two groups was amplified by polymerase chain reaction, respectively, and analyzed by electrophoresis on 9% nondenaturing polyacrylamide gel and stained with ethidium bromide. Differences between the two groups were compared using the chi(2) test. The results were there was no significant difference in allelic frequencies of 14-bp deletion polymorphism between normal control and RSA patients; frequency of -14 bp/+14 bp heterozygotes was significantly increased in RSA patients as compared with normal fertile controls. Our results are similar to a study of Indian women but contradictory to a study of Danish women. This discrepancy may be due to ethnic differences.

Fluctuation X-ray microscopy: a novel approach for the structural study of disordered materials

Measuring medium-range order is a challenging and important problem in the structural study of disordered materials. We have developed a new technique, fluctuation x-ray microscopy, that offers quantitative insight into medium-range correlations in disordered materials at nanometre and larger length scales. In this technique, which requires a spatially coherent x-ray beam, a series of speckle patterns are measured at a large number of locations in a sample using various illumination sizes. Examination of the speckle variance as a function of the illumination spot size allows the structural correlation length to be measured. To demonstrate this technique we have studied polystyrene latex spheres, which serve as a model for a dense random-packed glass, and for the first time have measured the correlation length in a disordered system by fluctuation X-ray microscopy. We discuss data analysis and procedures to correct for shot noise and detector noise. This approach could be used to explore medium-range order and subtle spatial structural changes in a wide range of disordered materials, from soft matter to nanowire arrays, semiconductor quantum dot arrays and magnetic materials.

Developing master keys to brain pathology, cancer and aging from the structural biology of proteins controlling reactive oxygen species and DNA repair

This review is focused on proteins with key roles in pathways controlling either reactive oxygen species or DNA damage responses, both of which are essential for preserving the nervous system. An imbalance of reactive oxygen species or inappropriate DNA damage response likely causes mutational or cytotoxic outcomes, which may lead to cancer and/or aging phenotypes. Moreover, individuals with hereditary disorders in proteins of these cellular pathways have significant neurological abnormalities. Mutations in a superoxide dismutase, which removes oxygen free radicals, may cause the neurodegenerative disease amyotrophic lateral sclerosis. Additionally, DNA repair disorders that affect the brain to various extents include ataxia-telangiectasia-like disorder, Cockayne syndrome or Werner syndrome. Here, we highlight recent advances gained through structural biochemistry studies on enzymes linked to these disorders and other related enzymes acting within the same cellular pathways. We describe the current understanding of how these vital proteins coordinate chemical steps and integrate cellular signaling and response events. Significantly, these structural studies may provide a set of master keys to developing a unified understanding of the survival mechanisms utilized after insults by reactive oxygen species and genotoxic agents, and also provide a basis for developing an informed intervention in brain tumor and neurodegenerative disease progression.

Incongruent evolution of chromosomal size in rice

To investigate genome size evolution, it is usually informative to compare closely related species that vary dramatically in genome size. A whole genome duplication (polyploidy) that occurred in rice (Oryza sativa) about 70 million years ago has been well documented based on current genome sequencing. The presence of three distinct duplicate blocks from the polyploidy, of which one duplicated segment in a block is intact (no sequencing gap) and less than half the length of its syntenic duplicate segment, provided an excellent opportunity for elucidating the causes of their size variation during the post-polyploid time. The results indicated that incongruent patterns (shrunken, balanced and inflated) of chromosomal size evolution occurred in the three duplicate blocks, spanning over 30 Mb among chromosomes 2, 3, 6, 7, and 10, with an average of 20.3% for each. DNA sequences of chromosomes 2 and 3 appeared to had become as short as about half of their initial sequence lengths, chromosomes 6 and 7 had remained basically balanced, and chromosome 10 had become dramatically enlarged (approximately 70%). The size difference between duplicate segments of rice was mainly caused by variations in non-repetitive DNA loss. Amplification of long terminal repeat retrotransposons also played an important role. Moreover, a relationship seems to exist between the chromosomal size differences and the nonhomologous combination in corresponding regions in the rice genome. These findings help shed light on the evolutionary mechanism of genomic sequence variation after polyploidy and genome size evolution.