Laminin receptor in lymph node negative breast carcinoma

Laminin receptor 1 expression in premalignant and malignant squamous lesions of the cervix

Laminin receptor 1 (LAMR) may have a role in the progression of premalignant squamous epithelial lesions to cervical cancer. Therefore, we aimed to investigate the expression of laminin receptor 1 (LAMR) in normal, premalignant, and malignant tissues of the uterine cervix. Paraffin blocks of 129 specimens with the diagnoses of normal cervical tissue (n = 33), cervical intraepithelial neoplasia (CIN) 1 (n = 30), CIN 2 (n = 14), CIN 3 (n = 28), and squamous cell carcinoma (n = 24) were immunohistochemically stained with LAMR antibody and its expression percentage, pattern, and intensity in these tissues were assessed. Compared to the other groups, the nonstaining with LAMR was highest in low grade squamous intraepithelial lesion (LSIL) (p < 0.0001). LAMR expression, which was positive in less than 50% of cells with weak staining, increased significantly between normal cervical epithelium and high-grade squamous intraepithelial lesion (HSIL) or invasive carcinoma, as well as between LSIL and HSIL (p < 0.0001). Between LSIL and invasive carcinoma, a significant increment was also observed for weak staining in less than 50% of cells (p < 0.001). LAMR expression, which was positive in more than 50% of cells with strong staining, was significantly higher in normal cervical tissue compared to the other groups (p < 0.0001). Disease progression related gradual increment of LAMR expression from normal cervical epithelium or LSIL towards HSIL or cervical cancer reveals that LAMR may play an important role in the transition from premalignant to malignant state in cervical lesions.

Expression and significance of laminin receptor in squamous cell carcinoma of the tongue

BACKGROUND

Laminin receptor is a non-integrin cell-surface receptor that binds laminin present on the basement membrane. It has been reported to be associated with infiltration and metastasis of various malignant tumors. However, no studies regarding tongue cancer have been reported. This study aimed to clarify the role of laminin receptor in squamous cell carcinoma of the tongue.

METHODS

We performed immunohistochemical staining of specimens from 66 patients with squamous cell carcinoma of the tongue and assessed laminin receptor expression and clinicopathological factors. As epithelial-mesenchymal transition has been shown to be associated with infiltration and metastasis of malignant tumors, staining for E-cadherin, vimentin, and N-cadherin were also performed.

RESULTS

Of 20 patients with postoperative recurrence, 14 exhibited high laminin receptor expression (p = 0.0025). Kaplan-Meier analysis revealed a significantly shorter time to postoperative recurrence for the high laminin receptor expression group than that for the low laminin receptor expression group (p = 0.0008). Based on multivariate analyses for postoperative recurrence, high laminin receptor expression was associated with poor prognosis (high expression vs. low expression; HR =3.19, 95% CI =0.92-11.08; p = 0.0682). There was a correlation between laminin receptor and N-cadherin (p = 0.0089) but not between laminin receptor and E-cadherin (p = 0.369) or vimentin (p = 0.4221).

CONCLUSION

These results suggest that high laminin receptor expression is a useful prognostic factor for postoperative recurrence and may be a target for molecular therapy to treat squamous cell carcinoma of the tongue.

Expression of Laminin Receptor 1 in Normal, Hyperplastic, and Malignant Endometrium

Laminin receptor 1 may have a role in the progression from endometrial hyperplasia with or without atypia to endometrial cancer. Therefore, we aimed to investigate the pattern, percentage, and intensity of laminin receptor 1 expression in normal, hyperplastic, and neoplastic endometrium. Paraffin blocks of 131 specimens with the diagnoses of normal endometrium (n=25), endometrial hyperplasia with atypia (n=21) or without atypia (n=55), and endometrial cancer (n=30) were immunostained with laminin receptor 1 antibody, and its expression percentage, pattern, and intensity in the epithelial cytoplasm, basement membrane, and endometrial stroma of these tissues were assessed. When compared with hyperplasia with or without atypia and endometrial cancer, the percentage of nonstaining with laminin receptor 1 in the epithelial basement membrane was higher (96%), and the percentage of <50% staining with laminin receptor 1 was lower (4%) in the normal endometrium (P=0.001). While a progressive increment in staining percentage and density of epithelial cytoplasm and basement membrane was noted through an orderly progression from normal endometrium to endometrial hyperplasia without atypia, endometrial hyperplasia with atypia, and cancer of endometrium (P<0.001), such a relationship was not found for the staining percentage and density of endometrial stroma (P>0.05). Disease progression-related gradual increment in laminin receptor 1 expression in the epithelial basement membranes of hyperplastic endometrium with or without atypia and cancer of endometrium reveals that it may play a substantial role in the transition from premalignant to the malignant state of endometrial lesions.

Novel patented therapeutic approaches targeting the 37/67 kDa laminin receptor for treatment of cancer and Alzheimer's disease

INTRODUCTION

The 37/67 kDa high-affinity laminin receptor (laminin receptor precursor/laminin receptor, LRP/LR) is a multi-faceted cellular receptor. It plays a vital role in the malignancy of various cancer types where it is seen to contribute to invasion, adhesion, apoptosis evasion and angiogenesis. Furthermore, it has been found to play an important role in facilitating the processes leading to neurotoxicity in Alzheimer's disease (AD). Various therapeutic options targeting this receptor have been patented with the outlook on application for the treatment/prevention of these diseases.

AREAS COVERED

The various roles that LRP/LR plays in cancer, AD and infectious diseases caused by viruses and bacteria have been examined in detail and an overview of the current patented therapeutic strategies targeting this receptor is given.

EXPERT OPINION

Molecular tools directed against LRP/LR, such as antibodies and small interfering RNA, could prove to be effective in the prevention of metastasis and angiogenesis while inducing apoptosis in cancers. Moreover, these strategies could also be applied to AD where LRP/LR is seen to facilitate the production and internalization of the neurotoxic Aβ peptide. This review provides a comprehensive overview of the mechanisms by which LRP/LR is involved in eliciting pathogenic events, while showing how the use of patented approaches targeting this receptor could be used to treat them.

67 laminin receptor promotes the malignant potential of tumour cells up-regulating lysyl oxidase-like 2 expression in cholangiocarcinoma

BACKGROUND

67 laminin receptor (67LR) plays an important role in the invasion and metastasis of cholangiocarcinoma, but its mechanism remains unclear.

AIMS

We investigated the clinical significance of 67LR and its relation to lysyl oxidase-like 2 (LOXL2) in 67LR-mediated invasion and metastasis in cholangiocarcinoma.

METHODS

The clinical significance of 67LR and LOXL2 expression and the prognosis of patients were investigated in 73 cancerous and 32 paracancerous tissues by immunohistochemistry. The impact of LOXL2 on invasion, metastasis and 67LR expression was evaluated in cholangiocarcinoma cells by shRNA or expressed-plasmid transfection.

RESULTS

Expression of 67LR was recognized in 35.62% cholangiocarcinoma tissue, and none in paracancerous tissues. LOXL2 was positively correlated with expression of 67LR. Expression of 67LR or LOXL2 in cholangiocarcinomas was significantly associated with lymph node metastasis, differentiation and poor overall survival. Cox analysis showed that 67LR can act as an independent prognostic biomarker of prognosis in cholangiocarcinoma patients. Expression of LOXL2 decreased by knockdown of 67LR and increased by overexpression of 67LR in cholangiocarcinoma cells. Knockdown of LOXL2 reduced invasion and metastasis in vitro and in vivo.

CONCLUSION

67LR may regulate the expression of LOXL2 to promote invasion and metastasis in cholangiocarcinoma cells. It could be used as an independent prognostic marker in cholangiocarcinoma patients.

Adhesion and Invasion of Breast and Oesophageal Cancer Cells Are Impeded by Anti-LRP/LR-Specific Antibody IgG1-iS18

Adhesion and invasion have been identified as the two key components of metastasis. The 37 kDa/67 kDa laminin receptor (LRP/LR) is thought to enhance these two processes thus endorsing the progression of cancer. Here we report on LRP/LR and the metastatic potential of MDA-MB 231 breast and WHCO1 oesophageal cancer cells. Western blot analysis revealed a significant increase in total laminin receptor precursor (LRP) levels of breast and oesophageal cancer cells in comparison to non-invasive MCF-7 breast cancer cells, whereas LRP/LR cell surface levels in both cell lines were not significantly different to those of MCF-7 cells as analysed by flow cytometry. Incubation of breast and oesophageal cancer cells with the anti-LRP/LR specific antibody, IgG1-iS18, resulted in significant reduction in the adhesive potential of WHCO1 and MDA-MB 231 cells by 92% and 16%, respectively. Moreover, invasion was significantly impeded by 98% and 25% for WHCO1 and MDA-MB 231 cells, respectively. Pearson's correlation coefficients proved a positive correlation between total LRP/LR levels and invasive potential as well as between the adhesive and invasive potential of breast and oesophageal cancer cells. Our findings suggest that through interference of the LRP/LR-laminin-1 interaction, anti-LRP/LR specific antibody IgG1-iS18 may act as a possible alternative therapeutic tool for metastatic breast and oesophageal cancer treatment.

In vitro inhibition of angiogenesis by antibodies directed against the 37kDa/67kDa laminin receptor

The 37kDa/67kDa laminin receptor (LRP/LR) is a central receptor mediating interactions between tumour cells and the basement membrane and is thereby a key player in adhesion and invasion, essential processes in metastatic cancer. To affect continued tumour growth, tumours induce angiogenesis for the constant delivery of nutrients and oxygen. This study aims to determine the blocking effect of the anti-LRP/LR specific antibody, W3 on the angiogenic potential of HUVE (human umbilical vein endothelial) cells. Flow cytometric analysis revealed that 97% of HUVE cells display cell surface LRP/LR. An angiogenesis assay was conducted employing HUVE cells seeded on the basement membrane reconstituent Matrigel™ supplemented with the pro-angiogenic factor vascular endothelial growth factor (VEGF). Post 18h incubation at 37°C tubular structures, namely tube lengths were assessed. Treatment of established tubular structures with 100 µg/ml anti-LRP/LR specific antibody completely blocked angiogenesis. Our findings suggest a central role of the 37kDa/67kDa LRP/LR in tube formation and recommends anti-LRP/LR specific antibodies as potential therapeutic tools for treatment of tumour angiogenesis.

Downregulation of the non-integrin laminin receptor reduces cellular viability by inducing apoptosis in lung and cervical cancer cells

The non-integrin laminin receptor, here designated the 37-kDa/67-kDa laminin receptor (LRP/LR), is involved in many physiologically relevant processes, as well as numerous pathological conditions. The overexpression of LRP/LR on various cancerous cell lines plays critical roles in tumour metastasis and angiogenesis. This study investigated whether LRP/LR is implicated in the maintenance of cellular viability in lung and cervical cancer cell lines. Here we show a significant reduction in cellular viability in the aforementioned cell lines as a result of the siRNA-mediated downregulation of LRP. This reduction in cellular viability is due to increased apoptotic processes, reflected by the loss of nuclear integrity and the significant increase in the activity of caspase-3. These results indicate that LRP/LR is involved in the maintenance of cellular viability in tumorigenic lung and cervix uteri cells through the blockage of apoptosis. Knockdown of LRP/LR by siRNA might represent an alternative therapeutic strategy for the treatment of lung and cervical cancer.

Laminin peptide YIGSR induces collagen synthesis in Hs27 human dermal fibroblasts

The dermal ECM is synthesized from fibroblasts and is primarily compromised of fibrillar collagen and elastic fibers, which support the mechanical strength and resiliency of skin, respectively. Laminin, a major glycoprotein located in the basement membrane, promotes cell adhesion, cell growth, differentiation, and migration. The laminin tyrosine-isoleucine-glycine-serine-arginine (YIGSR) peptide, corresponding to the 929-933 sequence of the β1 chain, is known to be a functional motif with effects on the inhibition of tumor metastasis, the regulation of sensory axonal response and the inhibition of angiogenesis through high affinity to the 67kDa laminin receptor. In this study, we identified a novel function of the YIGSR peptide to enhance collagen synthesis in human dermal fibroblasts. To elucidate this novel function regarding collagen synthesis, we treated human dermal fibroblasts with YIGSR peptide in both a time- and dose-dependent manner. According to subsequent experiments, we found that the YIGSR peptide strongly enhanced collagen type 1 synthesis without changing cell proliferation or cellular MMP-1 level. This YIGSR peptide-mediated collagen type 1 synthesis was modulated by FAK inhibitor and MEK inhibitor. This study clearly reveals that YIGSR peptide plays a novel function on the collagen type 1 synthesis of dermal fibroblasts and also suggests that YIGSR is a strong candidate peptide for the treatment of skin aging and wrinkles.

Anti-LRP/LR-specific antibody IgG1-iS18 significantly reduces adhesion and invasion of metastatic lung, cervix, colon and prostate cancer cells

The 37-kDa/67-kDa laminin receptor [laminin receptor precursor/high-affinity laminin receptor (LRP/LR)] is thought to play a major role in invasion and adhesion, key components of metastatic cancer. Lung cancer, cervical cancer, colon cancer and prostate cancer are among the top 10 cancer types worldwide. Here, we report that LRP/LR levels on the surface of lung cancer cells, cervical cancer cells, colon cancer cells and prostate cancer cells are significantly increased compared to non-tumorigenic fibroblasts. Adhesion of lung cancer cells, cervical cancer cells, colon cancer cells and prostate cancer cells to laminin-1 is significantly reduced, employing the anti-LRP/LR-specific antibody IgG1-iS18. Invasion of these cell lines into the Matrigel™ matrix was significantly impeded with IgG1-iS18. The Pearson's correlation coefficient proves a correlation between LRP/LR cell-surface levels and invasion potential, as well as adhesion and invasion, respectively. Our findings suggest that IgG1-iS18 antibody might act as alternative therapeutic tool for treatment of various metastatic cancer types.

The 67 kDa laminin receptor: structure, function and role in disease

The 67LR (67 kDa laminin receptor) is a cell-surface receptor with high affinity for its primary ligand. Its role as a laminin receptor makes it an important molecule both in cell adhesion to the basement membrane and in signalling transduction following this binding event. The protein also plays critical roles in the metastasis of tumour cells. Isolation of the protein from either normal or cancerous cells results in a product with an approx. molecular mass of 67 kDa. This protein is believed to be derived from a smaller precursor, the 37LRP (37 kDa laminin receptor precursor). However, the precise mechanism by which cytoplasmic 37LRP becomes cell-membrane-embedded 67LR is unclear. The process may involve post-translational fatty acylation of the protein combined with either homo- or hetero-dimerization, possibly with a galectin-3-epitope-containing partner. Furthermore, it has become clear that acting as a receptor for laminin is not the only function of this protein. 67LR also acts as a receptor for viruses, such as Sindbis virus and dengue virus, and is involved with internalization of the prion protein. Interestingly, unmodified 37LRP is a ribosomal component and homologues of this protein are found in all five kingdoms. In addition, it appears to be strongly associated with histones in the eukaryotic cell nucleus, although the precise role of these interactions is not clear. Here we review the current understanding of the structure and function of this molecule, as well as highlighting areas requiring further research.

Altered expression of metastasis-associated and regulatory molecules in effusions from breast cancer patients: a novel model for tumor progression

PURPOSE

The aim of this study was to characterize phenotypic alterations along the progression of breast carcinoma from primary tumor to pleural effusion through analysis of the expression of proteases, laminin receptors (LRs), and transcription factors involved in invasion and metastasis.

EXPERIMENTAL DESIGN

The material studied consisted of 60 malignant pleural effusions from breast cancer patients and 68 corresponding solid tumors (37 primary and 31 metastatic tumors). Expression of matrix metalloproteinases [MMPs (MMP-1, MMP-2, MMP-9, and MMP-14)], the MMP inhibitor tissue inhibitor of metalloproteinase-2, the MMP inducer EMMPRIN, the 67-kDa LR, the alpha6 integrin subunit, and the transcription factors AP-2, Ets-1, and PEA3 was studied using immunohistochemistry, mRNA in situ hybridization, reverse transcription-polymerase chain reaction, zymography, and flow cytometry. Hormone receptor (estrogen receptor and progesterone receptor) status and c-erbB-2 status were also studied.

RESULTS

Significantly reduced estrogen receptor (P < 0.001) and progesterone receptor (P = 0.001) expression was seen in effusions compared with primary tumors, with opposite findings for c-erbB-2 (P = 0.003). Tumor cell MMP-2 protein expression in effusions was higher than that in primary tumors (P < 0.001) and lymph node metastases (P = 0.01). In situ hybridization demonstrated higher MMP-2 (P = 0.007), PEA3 (P = 0.038), and EMMPRIN (P = 0.026) mRNA expression in effusions. The time to progression from primary tumor to effusion was significantly shorter for patients whose primary tumors expressed MMP-1 (P = 0.016) and who expressed the 67-kDa LR protein in primary tumor (P = 0.007) and effusion (P = 0.015).

CONCLUSIONS

Our data provide documented evidence of molecular events that occur during the progression of breast carcinoma from primary tumor to effusion. The coordinated up-regulation of MMP-2 and Ets transcription factors in carcinoma cells in effusions is in full agreement with our previous reports linking these factors to poor prognosis in ovarian cancer. The rapid progression to effusion in cases showing MMP-1 and 67-kDa LR expression in primary tumor cells links aggressive clinical behavior with expression of metastasis-associated molecules in this setting.

Infliximab monotherapy in psoriasis: A case of rapid clinical and histological response

BACKGROUND

Psoriasis is a common chronic relapsing, inflammatory, hyperproliferative skin disorder with genetic predisposition. There is currently no experimental model for psoriasis and the pathogenesis is not fully understood. Psoriatic plaques have been shown to contain increased levels of cytokines, including tumor necrosis factor alpha (TNF-alpha). Anti-tumor necrosis factor therapy with infliximab has been shown to be highly effective in recalcitrant psoriasis.

METHODS

We evaluated the efficacy and timeline of histological changes in a psoriatic plaque following infliximab infusion. A patient with severe recalcitrant plaque psoriasis was clinically and histologically assessed for improvement.

RESULTS

We found rapid clinical improvement with infliximab accompanied by histopathological changes. The earliest effects were seen on neutrophils and lymphocytes whereas keratinocyte normalization was not evident at the early stages.

CONCLUSION

Infliximab is not only an effective agent in the treatment of psoriasis but appears to have a very rapid onset of action.

Evaluation of superficial basal cell carcinomas after treatment with imiquimod 5% cream or vehicle for apoptosis and lymphocyte phenotyping

OBJECTIVE

To characterize the immune response and the apoptotic pathways that result in regression of imiquimod-treated basal cell carcinomas (BCCs).

METHODS

The trial was conducted as an open-label, matched controlled, nonrandomized study. Twelve patients were assigned as either active-treatment patients or matched control subjects. After treatment, lesions were excised and stained for CD20, CD3, CD4, CD56, bcl-2, bax, caspase-3, and p53. Additionally, a DNA fragmentation assay was performed using the terminal deoxynucleotidyltransferase-mediated dUTP nick-end-labeling method.

RESULTS

All vehicle-treated BCCs (six of six) had residual tumor compared with four of six imiquimod-treated BCCs. A dense mononuclear infiltrate surrounded all of the imiquimod-treated tumors and only one of six vehicle-treated BCCs. Staining for CD20, CD3, and CD4 revealed that the infiltrate consisted primarily of T-helper lymphocytes; however, a significant portion of the cells stained positively for CD56, indicating the presence of natural killer cells. Imiquimod-treated BCCs stained more strongly for caspase-3 and to a lesser degree p53 as compared with vehicle-treated BCCs. No differences were seen in either bax or bcl-2 staining. Minimal apoptosis was seen with the terminal deoxynucleotidyltransferase-mediated dUTP nick-end-labeling assay in either group.

CONCLUSION

This study provides evidence that imiquimod's antitumorigenic effects are mediated via up regulation of local interferon-alpha levels and supports previous work, suggesting that increased natural killer cell activity may be an important factors explaining both spontaneous regression and IFN-alpha induced regression of BCC.

Expression of the 67 kDa laminin receptor and the alpha6 integrin subunit in serous ovarian carcinoma

The aim of this study was to analyze the expression of two laminin receptors, the 67 kDa laminin receptor (LBP) precursor and the alpha6 integrin subunit, in effusions and solid tumors of patients diagnosed with serous ovarian carcinoma and to evaluate their predictive role. Eighty-eight effusions and one hundred sixteen primary (= forty-one) and metastatic (= seventy-five) ovarian carcinomas were evaluated for expression of the above-mentioned mRNAs using in situ hybridization (ISH). LBP protein expression was studied in 24 effusions and 43 solid tumors using immunohistochemistry (IHC). Alpha6 integrin subunit protein expression was studied in 27 effusions using flow cytometry (FCM). Expression of LBP mRNA was frequently detected in both carcinoma (92 of 116 cases, 79%) and stromal (79 of 116 cases, 68%) cells in solid tumors. Expression was still higher in cancer cells in effusions (85 of 88 specimens, 96%). In contrast, alpha6 integrin subunit was less frequently detected in both solid tumors (33 of 116; 28% in carcinoma cells, 23 of 116; 20% in stromal cells) and effusions (36 of 88; 41%). LBP protein expression was found in 19 of 24 (79%) effusions and 40 of 43 (93%) solid tumors, and was higher in effusions of patients who received chemotherapy prior to tapping (P = 0.024). FCM showed protein expression of the alpha6 integrin subunit in 17 of 27 (63%) effusions. Expression of the alpha6 integrin subunit mRNA in tumor cells of solid lesions was significantly lower in solid tumors of FIGO stage-IV patients compared to those of patients diagnosed with stage-III-disease (P = 0.004), and its absence predicted significantly shorter overall survival (OS) in univariate analysis (P = 0.018). Absence of alpha6 integrin subunit protein expression using FCM predicted median OS of 12 months compared to 26 months for patients with tumors expressing the protein, although this finding did not reach significance (P = 0.27). In conclusion, as opposed to previous reports, both mRNA and protein expression of the alpha6 integrin subunit do not appear to be down-regulated in effusions compared to solid tumors. Loss of alpha6 integrin subunit mRNA (and possibly protein) expression is a novel prognostic marker in advanced-stage ovarian carcinoma. LBP mRNA and protein expression is independent of that of the alpha6 integrin subunit in both solid tumors and effusions of serous ovarian carcinoma.

Prognostic Significance of Laminin, Laminin Receptor, and Bone Marrow Micrometastases in Breast Cancer Patients

Laminin is a basement membrane glycoprotein implicated in a large number of biologic activities of cancer progression, many of which are mediated by the presence of the laminin receptor (67LR) on the cell membrane. We studied the correlations of laminin and its receptor with standardized and new prognostic factors (including bone marrow micrometastases) in a series of 112 patients with operable breast cancers. Laminin-positive cells were detected in 60% of the tumors and 67LR-positive cells in 55%; both were present in 35% of the cases. No association was found between laminin or 67LR positivity and pathologic tumor size, pathologic nodal status, grading, Ki-67, estrogen receptor status, progesterone receptor status, or bone marrow micrometastases. The only statistically significant association was with menopausal status and age, with a higher percentage of 67LR-positive tumors among premenopausal and younger patients. The median follow-up was approximately 7 years. The prognosis of disease-free survival was similar in the laminin-positive and laminin-negative subjects but was significantly better in 67LR-negative patients; there were no significant differences in overall survival. The prognostic role of laminin and 67LR in disease-free survival and overall survival varied according to nodal status. In the absence of nodal involvement, the risk of relapse (and death) was greater in the patients who were positive for laminin, 67LR, or both than in those who were negative for laminin, 67LR, or both; in the case of 4 or more involved nodes, the prognostic role of laminin and 67LR was reversed. These results did not change after adjustment for age, menopausal status, tumor status, nodal status, grading, or bone marrow micrometastases.

Expression of Fas-receptor on basal cell carcinomas after treatment with imiquimod 5% cream or vehicle

Treatment with imiquimod 5% cream, capable of inducing interferon (IFN)-alpha, effectively cures basal cell carcinoma (BCC), both clinically and histologically. IFN-alpha induces expression of CD95-receptor (FasR) on BCC cells, which normally fail to express Fas receptor (FasR). Expression of the FasR is postulated to lead to apoptosis via CD95 receptor-CD95 ligand (FasL) interaction. Absence of this receptor may be responsible for the longevity of the cells of BCCs by preventing them undergoing 'suicidal' apoptosis, as well as apoptosis induced by neighbouring BCC cells and/or by infiltrating T-lymphocytes. We examined the expression of FasR on BCC after very short-term exposure to imiquimod 5% cream or vehicle. In a double-blind study, 10 patients with BCC applied either imiquimod (n = 5) or vehicle (n = 5) five times per week for up to 2 weeks. At the end of treatment, the treated area was excised and examined for the presence or absence of FasR by immunoperoxidase staining of rat antihuman FasR with haematoxylin and eosin counterstaining. Histologically, BCC cells were present in all (5/5) of the vehicle-treated BCCs and in 4/5 of the imiquimod-treated BCCs. BCC cells expressed FasR in 3/4 imiquimod-treated BCCs but in none (0/5) of the vehicle-treated tumours. T-lymphocytes apposed to BCC cells were evident in all three imiquimod-treated BCCs expressing FasR and in none of the FasR-negative, vehicle-treated BCCs. Imiquimod-induced FasR-mediated apoptosis may contribute to the effectiveness of imiquimod 5% cream for the treatment of BCC.

p53-dependent downregulation of metastasis-associated laminin receptor

Based on observations suggesting a role for the tumor suppressor protein p53 in regulating expression of the 67-kDa laminin receptor precursor, 37LRP, we analysed the 37LRP promoter activity in a wild-type p53 (wt p53) ovarian carcinoma cell line and in a cisplatin-resistant subline with mutated p53. We observed an increased promoter activity in wt p53 cells as compared to the mutated-p53 line when the first intron of the 37LRP gene was present in the reporter construct. Cotransfection experiments showed that the promoter is downregulated by both wt and mutated p53. Deletion analysis of the first intron localized an enhancer activity in the first 5' 214 bp that upregulates both 37LRP and SV40 promoter activity and is repressed by both wt and mutant p53. Cotransfection, mutagenesis and gel-shift experiments identified a functional AP-2 cis-acting element in this intron region that is repressed by increased levels of both wt and mutated p53. Coimmunoprecipitation studies revealed AP-2 in physical association in vivo with both wt and mutated p53, indicating for the first time that interaction of p53 with AP-2 is involved in the repression mechanism and in the regulation of genes involved in cancer growth and progression.

Potential markers predicting distant metastasis in axillary node-negative breast carcinoma

Prognostic parameters for axillary node-negative (ANN) breast cancer are still rare. Our aim was to establish potential markers that predict distant metastasis in ANN breast carcinoma and permit detection of the patients with high metastasis risk. A case control study was designed that comprised 64 ANN patients who developed distant metastasis during a 5-10 year follow-up period, 64 ANN patients with recurrence-free survival and 64 node-positive (ANP) comparitors. Immunohistochemistry and/or in situ hybridization were used to detect nm23, Cathepsin-D (Cath-D), Epidermal Growth Factor Receptor (EGFR) and Laminin Receptor (LR) in 192 cases. A significantly lower expression of both nm23 mRNA and protein was found in the ANN-group with poor prognosis compared with the ANN-group with good prognosis (p < 0.01). The protein levels of Cath-D, EGFR and LR were significantly higher in the ANN-group with poor prognosis and in the ANP-group compared with the ANN-group with good prognosis (p < 0.01 or p < 0.05), but no differences were found between the poor ANN-group and the ANP-group. Multiple regression analysis showed a close correlation of nm23, Cath-D and EGFR expression with occurrence of distant metastasis of ANN breast carcinoma. All markers except nm23 correlated with conventional histopathologic criteria such as tumor grade, margin and vessel invasion. The results suggest the combined detection of nm23, Cath-D and EGFR as predictive markers of distant metastasis in ANN breast cancer patients. Quantitative analysis together with clinicopathologic factors could contribute to estimate the potential risk of metastasis and select individual therapy regimen.

32/67-kD laminin receptor expression in human colonic neoplasia: elevated transcript levels correlate with the degree of epithelial dysplasia

OBJECTIVE

The 32/67-kD laminin receptor is thought to be involved in tumor cell migration and metastasis formation, and enhanced expression was observed in human colorectal carcinoma. Our objective was to investigate further the expression of the 32/67-kD laminin receptor RNA in human colonic carcinogenesis.

METHODS

We obtained sections of human colonic tissues in various stages of malignant transformation and analyzed them by in situ hybridization.

RESULTS

Normal colonic mucosa displayed a gradient between crypt base and surface epithelium with lowest receptor RNA levels in superficial epithelial cells. Increased laminin receptor RNA expression was observed in epithelial cells of adenomas with positive correlation between transcript levels and the degree of epithelial dysplasia. At variance with published results, we did not observe significant differences in 32/67-kD laminin receptor transcripts between adenomas with high-grade dysplasia and invasive adenocarcinoma. However, adenocarcinoma metastases displayed significantly higher laminin receptor RNA levels than high-grade adenomas and primary carcinomas.

CONCLUSIONS

We propose a two-step mechanism which controls first, upregulation of laminin receptor RNA before the acquisition of an invasive phenotype in dysplastic epithelial cells, and second, a further upregulation in metastatic cells during the adenoma-carcinoma sequence of the colon.