A clinically relevant bi-cellular murine mammary tumor model as a useful tool for evaluating the effect of retinoic acid signaling on tumor progression.

BACKGROUND: The effect of retinoic acid (RA) on breast cancer progression is controversial. Our objective was to obtain information about breast cancer progression, taking advantage of the ER-negative murine mammary adenocarcinoma model LM38 (LM38-LP constituted by luminal (LEP) and myoepithelial-like cells (MEP), LM38-HP mainly composed of spindle-shaped epithelial cells, and LM38-D2 containing only large myoepithelial cells), and to validate the role of the retinoic acid receptors (RARs) in each cell-type compartment. MATERIALS AND METHODS: We studied the expression and functionality of the RARs in LM38 cell lines. We analyzed cell growth and cell cycle distribution, apoptosis, the activity of proteases, motility properties, and expression of the molecules involved in these pathways. We also evaluated tumor growth and dissemination in vivo under retinoid treatment. RESULTS: LM38 cell lines expressed most retinoic receptor isotypes that were functional. However, only the bi-cellular LM38-LP cells responded to retinoids by increasing RARß2 and CRBP1 expression. The growth of LM38 cell sublines was inhibited by retinoids, first by inducing arrest in MEP cells, then apoptosis in LEP cells. Retinoids induced inhibitory effects on motility, invasiveness, and activity of proteolytic enzymes, mainly in the LM38-LP cell line. In in-vivo assays with the LM38-LP cell line, RA treatment impaired both primary tumor growth and lung metastases dissemination. CONCLUSION: These in-vivo and in-vitro results show that to achieve maximum effects of RA on tumor progression both the LEP and MEP cell compartments have to be present, suggesting that the interaction between the LEP and MEP cells is crucial to full activation of the RARs.

Mast cell phenotypes and microvessels in non-small cell lung cancer and its prognostic significance.

The impact of interstitial inflammatory cells, such as mast cells, and angiogenesis on the prognosis of cancer patients has been reported in many solid tumors, although there is disagreement about their role. We undertook a retrospective study with tissue samples from 65 patients with stage I and II non-small cell lung cancer to assess the clinical pathologic role and prognostic significance of mast cells. Mast cell phenotypes were identified by immunohistochemistry for tryptase and chymase. In addition, we identified microvessels using the endothelial marker CD34. Mast cell and microvessel density was quantified by assessing immunopositive cells in the intratumoral and peritumoral zones of tumor specimens. Both mast cell and microvessel density was higher in the peritumoral zone than the intratumoral zone (P

Prognostic value of E-cadherin, beta-catenin, MMPs (7 and 9), and TIMPs (1 and 2) in patients with colorectal carcinoma.

BACKGROUND AND OBJECTIVES: Therapy of colorectal tumors (CRC) based on histology and clinical factors is insufficient to predict the evolution of each patient. The finding of molecular abnormalities able to differentiate subgroups of patients with bad prognosis will improve our ability to treat them successfully. Our purpose was to analyze retrospectively the prognostic input of E-cadherin, beta-catenin, metalloproteinases (MMPs) (7 and 9), and tissue inhibitors of metalloproteinases (TIMPs) (1 and 2) in patients with a follow-up period of 5 years. METHODS: Antigen expression was analyzed by immunohistochemistry. Prognostic evaluation was performed with the multivariate proportional hazards model. RESULTS: We demonstrated a concomitant loss of E-cadherin and beta-catenin at membranous level and an abnormal accumulation of nuclear beta-catenin. Besides, we found that all MMPs and TIMPs studied were overexpressed in CRC tissue. There was no association between the expression of any of these molecules and the known clinical-pathological parameters employed in CRC pathology. A multivariate analysis demonstrated that the overall survival could be independently predicted by the loss of E-cadherin and the overexpression of TIMP-2. CONCLUSIONS: The expression of E-cadherin and TIMP-2 could be relevant in determining the prognosis of CRC patients and providing a more accurate mechanism for their classification.

EGF-R and PDGF-R, but not bcl-2, overexpression predict overall survival in patients with low-grade astrocytomas.

BACKGROUND AND OBJECTIVES: Therapy of malignant glioma tumors is based on histology and clinical factors. However, comparable lesions may correspond with important prognostic differences. Our purpose was to analyze retrospectively the prognostic input of platelet-derived growth factor receptor (PDGF-R), epidermal growth factor (EGF-R), and bcl-2 expression in 103 malignant gliomas from uniformly treated patients. METHODS: The expression of the antigens was analyzed by immunohistochemistry (IHC). Prognostic evaluation was performed with the multivariate proportional hazards model. The follow-up period lasted 19 (5-122) months for survivors. RESULTS: We observed that almost 50% of gliomas showed high expression of PDGF-R, while a lower expression of EGF-R and bcl-2 was found. No association between the main prognostic factors in malignant glioma (sex, age, histological grade, and Karnofsky score) and the labeling index (LI) of these antigens was observed. We found that only PDGF-R and EGF-R overexpression were associated with a shorter survival in patients with World Health Organization (WHO) II astrocytomas, being both associations independent of known prognostic factors, as shown by Cox model. Besides, we confirmed other authors' results that high histological grade and low performance score were associated with worse prognosis. CONCLUSIONS: PDGF-R and EGF-R expression could be relevant in determining the prognosis of low-grade astrocytomas (LGAs) and in providing a more objective mechanism for their classification.