Breast development gives insights into breast disease

Aims : Studies of developing human breasts are essential for understanding the organogenesis as well as molecular pathogenesis of benign and malignant breast diseases. In this study we have examined the distribution of TGF-α, TGF-β1, tenascin-C and collagen type IV with the aim of starting to build a picture of the profile of molecules that may be involved in the development of the human breast.  

Methods and results

Ten fetal breasts (16 to 23 weeks of gestation) and 45 infant breasts, ranging in age from newborn to 2 years, were used in this study. Paraffin sections from these samples were immunostained with antibodies for these proteins and for Ki67 to elucidate the level of proliferative activity in different stages of breast development. TGF-α immunoreactivity was observed both in the stromal and the epithelial cells within fetal and infant breasts up to 25 days. TGF-β1 immunoreactivity was localized in the extracellular matrix. Tenascin-C was found around the neck of the developing breast bud and in the extracellular matrix of the infant with peaks in the newborn at 6–12 weeks. The immunoreactivity for type IV collagen was more intense in the region of the breast bud neck in the fetal breasts and reduced around the tips of lobular and terminal-end buds within the infant breasts.  

Conclusions

The distribution of the growth factors and extracellular matrix proteins within the developing human breast indicates that they play a significant role in different cellular compartments during morphogenesis and provides insights into breast disease.     

Growth and development of the human infant breast

Seventy-two samples of infant breasts, aged from newborn to 2 years, were collected at necropsy. Whole-mount preparations and histological sections were made. A system of classification was devised to study the extent of the structural development of the ductal system (morphological types I, II, and III) and the functional differentiation of the lining epithelium (functional stages I to V). There was no correlation between the age of the infant and the type of development of the ductal system. In contrast, the epithelial differentiation followed a chronological pattern, starting with secretory changes and apparently going through a period characterized by apocrine metaplasia before post-secretory involution. These epithelial changes were not associated with the morphological type of the ductal system. There were no distinguishing features between the breasts from the two sexes. Immunoperoxidase staining for actin and kappa-casein was carried out to study the myoepithelial cells and secretory cells, respectively. Myoepithelial cells were present at all stages and prominent staining for casein was observed up to 2 months of age. Embryonic-type adipose tissue was seen in 7 cases, in one of which it was associated closely with the developing ductal system. Extramedullary hematopoiesis was observed in the periductal connective tissue until 4 months of age. This paper describes the most extensive anatomical and histological study of the human infant breast to date and lays the foundation for a detailed study of the epithelial and stromal changes that take place during human breast development.     

A cross-study comparison of gene expression studies for the molecular classification of lung cancer.

PURPOSE: Recent studies sought to refine lung cancer classification using gene expression microarrays. We evaluate the extent to which these studies agree and whether results can be integrated. EXPERIMENTAL DESIGN: We developed a practical analysis plan for cross-study comparison, validation, and integration of cancer molecular classification studies using public data. We evaluated genes for cross-platform consistency of expression patterns, using integrative correlations, which quantify cross-study reproducibility without relying on direct assimilation of expression measurements across platforms. We then compared associations of gene expression levels to differential diagnosis of squamous cell carcinoma versus adenocarcinoma via reproducibility of the gene-specific t statistics and to survival via reproducibility of Cox coefficients. RESULTS: Integrative correlation analysis revealed a large proportion of genes in which the patterns agreed across studies more than would be expected by chance. Correlation of t statistics for diagnosis of squamous cell carcinoma versus adenocarcinoma is high (0.85) and increases (0.925) when using only the most consistent genes identified by integrative correlation. Correlations of Cox coefficients ranged from 0.13 to 0.31 (0.33-0.49 with genes selected for consistency). Although we find genes that are significant in multiple studies but show discordant effects, their number is approximately that expected by chance. We report genes that are reproducible by integrative analysis, significant in all studies, and concordant in effect. CONCLUSIONS: Cross-study comparison revealed significant, albeit incomplete, agreement of gene expression patterns related to lung cancer biology and identified genes that reproducibly predict outcomes. This analysis approach is broadly applicable to cross-study comparisons of gene expression profiling projects.     

Synthesis,supramolecular organization and thermotropic phase behaviour of N-acyltris(hydroxymethyl)aminomethane

Herein, we reported the supramolecular organization of N-acyltris(hydroxymethyl)aminomethane (NATM) in the solid state as well as in aqueous solution. Single crystal X-ray diffraction revealed that NATM adopts a fully interdigitized structure. The thermodynamic parameters associated with thermotropic phase behaviour of NATM was determined by differential scanning calorimetry. The molecular packing and phase state of the NATM analyzed by laurdan and prodan fluorescence supports the formation of an interdigitized phase in aqueous solution. The potential application of the self-assembled NATM vesicles was demonstrated through entrapping model drug, Rhodamine B.

Self assembly of N-acyltris(hydroxymethyl)aminomethane into interdigitized vesicles.     

Mucinous cancers have fewer genomic alterations than more common classes of breast cancer

Mucinous cancers of the breast are distinguished histologically by their abundant pools of mucin and low degree of nuclear pleomorphism. Relative to the more common breast cancers of no distinctive type (ductal carcinoma), mucinous cancers have a relatively favorable prognosis. In a study of chromosomal changes in mucinous cancers, we evaluated the extent of loss of heterozygosity (LOH) at chromosomal regions commonly deleted in usual infiltrating ductal carcinoma, including markers on chromosomal arms 1p, 1q, 3p, 6q, 8p, 9p, 11p, 11q, 13q, 16q, 17p, and 17q. Remarkably, we found an average frequency of LOH of only 1.9 of these 12 chromosomal arms in 18 cases of mucinous carcinoma, compared to an average frequency of LOH of 6.4 of these same chromosomal arms in cases of infiltrating ductal cancer. In three of the 18 cases of mucinous carcinoma studied, including one case with regional lymph node metastases, no LOH was seen at any of the 12 chromosomal regions studied. We considered the possibility of other chromosomal loci being more commonly affected in mucinous cancers and conducted comparative genomic hybridization on six of the cases. These studies demonstrated a low overall frequency of genomic copy number changes (mean of 3.1 changes per case) and failed to reveal any other chromosomal locus with frequent losses that had not been evaluated by microsatellite analysis. Together, these data indicate that mucinous cancers of the breast do not have the extensive genomic alterations that are typically found in more common variants of breast cancer. Thus, mucinous cancers most likely have less genetic instability than most other forms of breast cancer and the molecular pathogenesis of this form of breast cancer is likely to be substantially different than that of usual ductal breast cancer.     

Nuclear genes involved in mitochondria-to-nucleus communication in breast cancer cells

Background  

The interaction of nuclear and mitochondrial genes is an essential feature in maintenance of normal cellular function. Of 82 structural subunits that make up the oxidative phosphorylation system in the mitochondria, mitochondrial DNA (mtDNA) encodes 13 subunits and rest of the subunits are encoded by nuclear DNA. Mutations in mitochondrial genes encoding the 13 subunits have been reported in a variety of cancers. However, little is known about the nuclear response to impairment of mitochondrial function in human cells.     

Modulation of carcinogenic response and antioxidant enzymes of rats administered with 1,2-dimethylhydrazine by Picroliv

The effect of Picroliv treatment on the carcinogenic response and, hepatic and renal antioxidant enzymes of rats administered with 1,2-dimethylhydrazine hydrochloride (DMH) was studied in male Sprague-Dawley rats. DMH-induced hepatic carcinogenic response and necrosis were inhibited by oral administration of Picroliv (40 and 200 mg/kg). Liver gamma-glutamyl transpeptidase, which was elevated to 0.41 +/- 0.06 nmol/mg protein by DMH administration was found to be reduced to 0.22 +/- 0.04 and 0.18 +/- 0.03 nmol/mg protein by Picroliv treatment 40 and 200 mg/kg, respectively. Elevated number of Argyrophilic Nucleolar Organizer Region dots and clusters, an index of proliferation, of DMH treated rat liver was reduced by Picroliv treatment. DMH-induced depletion of hepatic and renal antioxidant enzymes such as catalase and superoxide dismutase levels were restored to normal by Picroliv treatment. Picroliv treatment reduced the DMH-induced elevation of lipidperoxidation in liver, kidney and serum. Elevated levels of serum total bilirubin by DMH administration was reduced by Picroliv treatment. Depleted renal glutathione S-transferase and hepatic glutathione levels after DMH administered rats were found to be significantly increased by Picroliv treatment. Histological analysis of the DMH administered rat liver showed hepatic cell necrosis, coalescent nodular areas and cystic hyperplasia of the bile ducts with inflammation. Picroliv treated liver resembled normal liver except the presence of a few degenerating cells. Renal anatomy was not altered by DMH administration.     

Inhibition of chemical carcinogenesis by berberine in rats and mice

Berberine, an alkaloid isolated from the plant Berberis aristata, has been found to inhibit significantly the carcinogenesis induced by 20-methylcholanthrene (200 microg/0.1 mL/mouse) or N-nitrosodiethylamine (NDEA; 0.02% NDEA in distilled water, 2.5 mL/animal by gavage, five days a week for 20 weeks) in a dose-dependent manner in small animals. Administration of berberine (0.5, 2.5 or 5.0 mg kg(-1)) could reduce significantly the incidence of tumour in animals after an injection of 20-methylcholanthrene and increased their life span compared with the control. When berberine (10, 25 or 50 mg kg(-1)) was administered simultaneously with NDEA, the markers of liver injury (liver weight, gamma-glutamyl transpeptidase activity and glutathione S-transferase level) were reduced significantly compared with animals treated with NDEA only, which resulted in all the values being elevated. A similar decrease was noted in the serum levels of lipid peroxide, bilirubin and glutamate pyruvate transaminase. Morphology of liver tissue and levels of marker enzymes indicated that berberine offered protection against chemical carcinogenesis.     

Microsatellite instability is uncommon in breast cancer.

In some tumors, defects in mismatch repair enzymes lead to errors in the replication of simple nucleotide repeat segments. This condition is commonly known as microsatellite instability (MSI) because of the frequent mutations of microsatellite sequences. Although the MSI phenotype is well recognized in some colon, gastric, pancreatic, and endometrial cancers, reports of MSI in breast cancer are inconsistent. We report here our experience with >10,000 amplifications of simple nucleotide repeats in noncoding genomic regions using DNA from 267 cases of breast cancer, including cases that represent all major histological types of breast cancer. We rarely (10 reactions) found unexpected bands in amplifications of tumor DNA that were not present in amplifications of normal DNA. Moreover, repeats of these reactions did not confirm microsatellite instability in a single case. We also evaluated the simple nucleotide repeats in the transforming growth factor type II receptor, insulin-like growth factor type II receptor, BAX, and E2F-4 genes, which are frequently mutated in tumors with microsatellite instability. No mutations of these genes were found in any of the 30 breast cancer cell lines and 61 primary breast cancer samples examined. These results indicate that mismatch repair errors characteristic of the MSI phenotype are uncommon in human breast cancer.