Proliferation, basement membrane changes, metastasis and vascularization patterns in human breast cancer

Elastin molecular aging promotes MDA-MB-231 breast cancer cell invasiveness

Elastin is a long-lived extracellular matrix protein responsible for the structural integrity and function of tissues. Breast cancer elastosis is a complex phenomenon resulting in both the deposition of elastotic masses and the local production of elastin fragments. In invasive human breast cancers, an increase in elastosis is correlated with severity of the disease and age of the patient. Elastin-derived peptides (EDPs) are a hallmark of aging and are matrikines - matrix fragments having the ability to regulate cell physiology. They are known to promote processes linked to tumor progression, but their effects on breast cancer cells remain unexplored. Our data show that EDPs enhance the invasiveness of MDA-MB-231 breast cancer cells through the engagement of matrix metalloproteases 14 and 2. We therefore suggest that elastosis and/or an aged stroma could promote breast cancer cell invasiveness.

Histological and biological characteristics of microinvasion in mammary carcinomas < or = 2 cm in diameter

Fifty-two mammary carcinomas, 2 cm or less in diameter, were examined in order to clarify the morphology and biology of microinvasion. The morphological characteristics of microinvasion of carcinomas include: (i) a loss of myoepithelial cells and a rupture with concomitant loss of collagen IV and laminin in the basement membrane of involved mammary glands; and (ii) budding of carcinomas from the rupture into the stroma. When microinvasion was defined as a rupture of < 200 microm in the basement membrane with invasion, the number of microinvasions per 1 mm of basement membrane was larger in the tumors in which the area of invasion was larger. The prevalence of microinvasion showed a significant correlation with lymph node metastasis and the rate of histological deviation, while no correlation of expression of either estrogen receptors or progesterone receptors and c-erbB-2 protein was found. The study clarified that the early invasion of mammary carcinomas could be detected by the immunohistochemical method using anti-smooth muscle actin, laminin and collagen IV antibodies. The study also suggested that microinvasion might be an indicator of lymph node metastasis in mammary carcinomas < or = 2 cm diameter.

Interstitial stroma and carcinogenesis: ultrastructural observations in the rat bladder treated with N-butyl-N-(4-hydroxybutyl)nitrosamine

This study describes ultrastructural alterations of the interstitial stroma in the rat bladder epithelium during N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN)-induced bladder carcinogenesis using scanning (SEM) and transmission (TEM) electron microscopy with NaOH treatment. The results obtained with SEM demonstrated the occurrence and development of stroma protrusions which exhibited pipe-like structures in the rat bladder epithelium following administration of BBN. Number and size of blood vessel sections also gradually increased both in the stroma and within the layer of the proliferated epithelial cells as examined by light microscopy (LM) and TEM. In this study stroma alterations were not only observed in malignant lesions of rat bladder, but hyperplastic lesions were also accompanied by stroma alterations. It is suggested that: (1) the interstitial stroma of the rat bladder epithelium may exhibit pathological changes in structure and these changes may correlate with the progression of epithelial cell proliferation following administration of BBN and (2) one of the most important alterations in the stroma is the occurrence of neovascularization, which may induce structural modification of the stroma in the processes of bladder tumor growth and development.

Location of 72-kd metalloproteinase (type IV collagenase) in untreated prostatic adenocarcinoma

The aim of the study was to investigate the location of the expression of 72-kd metalloproteinase (MMP-2) in relation to the distribution of type IV collagen in untreated prostatic adenocarcinoma (PAc). Twenty formalin-fixed, paraffin-embedded PAc cases, in which high grade prostatic intraepithelial neoplasia (PINhigh) was occasionally present, were immunohistochemically examined. Type IV collagen immunoreactivity showed the presence of a basement membrane (BM) at the epithelial-stromal junction. In cribriform and solid/trabecular PAc, the staining was focally disrupted. In acinar PAc, the BM immunostained by anti-type IV collagen was observed around the individual acini, with occasional thinning and fragmentation. Immunostaining for MMP-2 was heterogeneous in intensity and location. Cribriform and solid/trabecular PAc showed weak cytoplasmic immunostaining for MMP-2; both moderately and intensely stained cells were seen in the cell layer adjacent to the stroma; intense immunostaining was shown by small clusters of neoplastic cells or single neoplastic cells located in the stroma which also showed thinning and fragmentation of BM staining. In acinar PAc, weak cytoplasmic immunostaining for MMP-2 was seen throughout most areas of the tumours, whereas moderately and intensely stained cells were observed less frequently than in cribriform and solid/trabecular adenocarcinoma. Intense immunostaining of single or small clusters of neoplastic cells located in the stroma was rarely observed and, as for cribriform and solid/trabecular PAc, mainly located towards the periphery of the tumour nodules. BM stained by anti-type IV collagen was preserved in normal prostate and in PIN, some thinning being present in the latter. The pattern and intensity of immunoreactivity for MMP-2 in PIN was similar to that of cribriform and solid/trabecular PAc, whereas normal ducts and acini showed weak immunostaining in most of the secretory cells and moderate to strong immunoreactivity in scattered basal cells. Thus, MMP-2 appeared basically expressed in cells which lie in direct contact with the stroma. This underlined the importance of evaluating the MMP-2 location in relation to basement membrane degradation and tumour invasion.

Intraductal carcinoma (ductal carcinoma in situ) of the breast. A comparison of pure noninvasive tumors with those including different proportions of infiltrating carcinoma

BACKGROUND

Several studies have suggested that ductal carcinoma in situ (DCIS) of the comedo type (variably defined) is biologically more aggressive than other patterns of DCIS and more likely to progress rapidly to invasive carcinoma.

METHODS

Eighty-five pure DCISs were compared histopathologically with 64 carcinomas containing both intraductal and infiltrating ductal components (mixed DCIS/IDC).

RESULTS

Solid DCIS with and without necrosis was seen more frequently seen in the mixed DCIS/IDC series, especially in cases with less than 50% DCIS. Periductal stromal inflammation and multifocality also were seen more frequently in mixed DCIS/IDC than in pure DCIS. High nuclear grade and high mitotic activity were also more common in the DCIS component of the mixed cases and were well correlated with the intraductal and infiltrating components of the same tumors in most of the cases. The frequency of axillary lymph node metastases was correlated with the proportions of stromal invasion but not with the DCIS subtypes. When the criteria (solid growth pattern, high nuclear grade, and central necrosis) for the diagnosis of intraductal comedocarcinoma were analyzed separately, the first of these correlated most strongly with mixed DCIS/IDC compared with pure DCIS, the second less strongly, and the third not at all, although central necrosis has been considered the main or only diagnostic criterion for comedocarcinoma in several previous reports.

CONCLUSIONS

Solid growth pattern and high nuclear grade are the most important histopathologic features of DCIS used to predict progression to invasive carcinoma. No major changes between the intraductal and invasive elements of the same tumors were noted, but other studies have suggested that markers of aggressiveness either increase or decrease in the progression to invasion. These conflicting data require further investigation.