Immunohistochemical Study of 49 Cutaneous Melanomas: P53, PCNA, Bcl-2 Expression and Multidrug Resistance

Cell proliferation in cutaneous malignant melanoma: relationship with neoplastic progression

The establishment of the diagnosis of cutaneous malignant melanoma (CMM) always calls for histopathological confirmation. Further to the recognition of the CMM aspects, immunohistochemistry is helpful, in particular, in determining the size of the replicative compartment and the activity in each of the cell cycle phases (G(1), S, G(2), M). The involvement of cancer stem cells and transient amplifier cells in CMM genesis is beyond doubt. The proliferation activity is indicative of the neoplastic progression and is often related to the clinical growth rate of the neoplasm. It allows to distinguish high-risk CMM commonly showing a high growth rate, from those CMMs of lower malignancy associated with a more limited growth rate. The recruitment and progression of CMM cells in the cell cycle of proliferation depend on mitogen-activated protein kinase (MAPK) pathway and result from a loss of control normally involving a series of key regulatory cyclins. In addition, the apoptotic pathways potentially counteracting any excess in proliferative activity are out of the dependency of specific regulatory molecular mechanisms. Key molecular components involved in the deregulation of the growth fraction, the cell cycle phases of proliferation, and apoptosis are presently described in CMM.

Prognostic significance of regulators of cell cycle and apoptosis, p16(INK4a), p53, and bcl-2 in primary mucosal melanomas of the head and neck

Abnormalities in cell cycle regulation, tumor suppressor gene functions and apoptosis are frequent events in tumorigenesis. Their role in the pathogenesis and prognosis of primary mucosal melanomas (MM) of the upper aerodigestive tract remains unknown. Sixty-four patients (40 men, 24 women, median age 64 years) with MM were included in this study; 32 had tumors in the nasal/paranasal cavities, 28 in the oral cavity and 4 in the pharynx. Archival tissues from 47 initial mucosal tumors, 17 mucosal recurrences, and 13 nodal/distant metastases were subjected to immunohistochemistry using antibodies against p16, p53, and bcl-2. The results were correlated with histological features and survival data. Expressions of p16, p53, and bcl-2 proteins were seen in 25% (N=19/76), 21% (N=16/76), and 74% (N=56/76) of all tumors, respectively. bcl-2 expression in the initial tumors was associated with significantly longer overall and disease specific survival (3.3 vs. 1.5 years, P ≤ 0.05). Expression of p16 was increasingly lost, from 32% in initial tumors to 12% in recurrent and 15% in metastatic tumors (P=0.06). Tumors comprised of undifferentiated cells were significantly more p53 positive than epithelioid or spindle cells (80% vs. 33%, P=0.02). Expression of these markers did not correlate with necrosis, or vascular and/or deep tissue invasion. Expression of bcl-2 is associated with better survival in MM. Loss of p16 was seen with tumor progression whereas aberrant p53 expression was frequent in undifferentiated tumor cells.

The emerging role of the thrombin receptor (PAR-1) in melanoma metastasis--a possible therapeutic target

Melanoma remains as the deadliest form of skin cancer with limited and inefficient treatment options available for patients with metastatic disease. Within the last decade, the thrombin receptor, Protease Activated Receptor-1, has been described as an essential gene involved in the progression of human melanoma. PAR-1 is known to activate adhesive, invasive and angiogenic factors to promote melanoma metastasis. It is overexpressed not only in metastatic melanoma cell lines but is also highly expressed in metastatic lesions as compared to primary nevi and normal skin. Recently, PAR-1 has been described to regulate the gap junction protein Connexin 43 and the tumor suppressor gene Maspin to promote the metastatic melanoma phenotype. Herein, we review the role of PAR-1 in the progression of melanoma as well as utilizing PAR-1-regulated genes as potential therapeutic targets for melanoma treatment.

Maspin and Mutant p53 expression in malignant melanoma and carcinoma: use of tissue microarray

Maspin (mammary serine protease inhibitor), a member of the serpin family, has been shown to inhibit angiogenesis, tumor invasion, and metastasis. Previous studies suggest a p53-dependent regulatory pathway of maspin protein expression. Its loss correlates with progression of disease in both breast and prostate cancer. We studied the in vivo correlation of maspin expression with p53 mutation in malignant melanoma (MM) with and without use of tissue microarray (TMA). Seventy-seven MMs were immunostained on individual slides for maspin and p53 expression. Results were validated in 1 slide for each marker on a TMA system (TARP-2) with 498 tissue cores (0.6-mm diameter) from MM, other tumors, and normal tissue. The relationship between maspin and p53 in MM and carcinomas of other sites (breast, ovary, colon, lung, and prostate) was delineated using Pearson chi analysis. The inverse relationship between maspin and p53 expression predicted by hypothesized p53 regulation of maspin transcription, or any other correlation between these 2 markers, is not demonstrated in MM cases, using either classic individual slide (P=0.20) or TMA (P=0.85) methods when cutoffs for both markers are set at 10% or greater of cells staining. Even when cutoffs are altered with respect to either intensity or percentage of cells staining, no relationship is demonstrated between these markers, with either TMA or the conventional slide method. TMA immunostaining also showed no such relationship in carcinomas of the various other sites sampled-including breast and prostate, where previous studies have suggested a linkage. Despite published experimental evidence linking these 2 markers, this study failed to demonstrate correlation between maspin loss and p53 expression in MM using both individual slides and TMA, or in TMA of other carcinomas. Use of TMA is a quick, easy, and inexpensive method of immunohistochemical analysis of large numbers of cases, both to validate results obtained from individual slides and to assess specificity in a variety of neoplasms. However, heterogeneity and minimal tumor may lead to variable results.

Downregulation of cell cycle modulators p21, p27, p53, Rb and proapoptotic Bcl-2-related proteins Bax and Bak in cutaneous melanoma is associated with worse patient prognosis: preliminary findings

BACKGROUND

Cutaneous melanoma is a tumor with high metastatic potential, but the mechanisms leading to progression are still not fully understood. To provide further molecular basis for understanding the progression of melanoma, the aim of this study was to examine the expression pattern of cell cycle modulators (p21, p27, p53 and Rb) and proapoptotic multidomain Bcl-2 related proteins (Bax and Bak) and to analyze its differences in patients with and without progression stages.

METHODS

We have studied 31 patients with cutaneous melanoma at stage IIa (Breslow thickness 1.5-4.0 mm), and follow them for 10-year period. Eighteen of these patients developed metastasis. The determination of selected molecular markers participating in cell cycle regulation and apoptosis was performed by immunohistochemistry.

RESULTS

We have observed a significant increase in the loss of expression of the Bax, Bak, p21, p27, p53 and Rb. The analysis of the relationship between these downregulated markers and Breslow thickness showed significant positive correlation (r=0.556, p=0.029) and predictive value if thickness below 2.3 mm (OR=3.0, 95% CI=0.312-28.84).

CONCLUSIONS

Our study showed that the downregulation of the markers associated with cell cycle control and apoptosis is of great value in predicting malignant transformation and in assessing the risk of metastases development for 10-year follow-up period.

[Isolation of mitochondrial DNA binding proteins which are specific for maize cox1 promoter]

We purified DNA binding proteins which interact with the promoter region of cox1 gene from maize mitochondria. Presence of poly[dIdC-dIdC] and KCl in concentrations up to 500 mM had no influence on binding efficiency demonstrating high specificity of complexes formed. Surprisingly, we did not detect DNA binding when probes containing promoter regions of other mitochondrial genes (cox3, rrn26) were used. Mobility shift competition studies also suggest that the protein posseses binding specificity towards cox1 promoter. The core motif AAGTA proved to be necessary for DNA binding. Using combination of EMSA and elution of proteins from PAG we showed that DNA-protein complex formed contains three polypeptides with molecular mass 60, 44 and 22 kD. We suggest that the isolated proteins may play an important role in the regulation of plant cox1 gene transcription.

CD10 protein expression in tumor and stromal cells of malignant melanoma is associated with tumor progression

CD10 antigen is a 100-kDa-cell surface zinc metalloendopeptidase expressed in a variety of normal and neoplastic lymphoid and nonlymphoid tissues including melanomas. It was recently shown that metastatic melanomas express more CD10 than primary tumors. We evaluated CD10 expression in tumor and stromal cells in 70 biopsies with primary and 28 with metastatic malignant melanomas. Ki-67, Bcl-2, and Bax were also examined to investigate whether CD10 expression is associated with tumor proliferation index or factors of apoptosis. Formalin-fixed/paraffin-embedded tissues were studied by immunohistochemistry. More advanced primary tumors had higher CD10 expression in the tumor cells (r = 0.27, P = 0.03 for Clark levels and r = 0.29, P = 0.02 for Breslow) and higher Ki-67 proliferation fraction (r = 0.32, P = 0.007 for Clark levels and r = 0.32, P = 0.001 for Breslow). Similarly, CD10 expression in the intratumoral stromal cells was also higher in primary tumors with higher Clark level (P = 0.04, linear-by-linear association) and tumor thickness according to Breslow (r = 0.33, P = 0.01). The presence of CD10+ peritumoral stromal cell cuffs was also positively associated with tumor thickness according to Breslow (r = 0.27, P = 0.05). Also, expression of CD10 and Ki-67 were significantly higher in metastatic than in primary tumors (P = 0.01 and 0.02 respectively), but Bcl-2 expression was higher in primary melanomas (P = 0.02). We conclude that CD10 expression in malignant melanoma is associated with tumor progression.

HER-2/neu and p53 in osteosarcoma: an immunohistochemical and fluorescence in situ hybridization analysis

The overexpression of HER-2/neu and p53 has been associated with poor outcome in many neoplasms. Their role in patients with osteosarcoma is unclear. We studied the expression of HER-2/neu and p53 in 22 osteosarcoma samples (from 20 patients--2 had locally recurrent disease) biopsied at the University of Medicine and Dentistry of New Jersey (UMDNJ) from 1996-2000 using both immunohistochemical (IHC) and fluorescence in situ hybridization (FISH) analysis. Fourteen patients (14 samples) presented with Stage II and 6 patients (8 samples) presented with Stage III disease. Median follow-up is two years (range one year to five years). Four of 22 (18%) samples showed focal membranous or cytoplasmic positivity for HER-2/neu and six of 22 samples (27%) showed nuclear positivity for p53 by IHC analysis. In contrast, none of 22 tested samples showed gene amplification for HER-2/neu by FISH analysis. Seven of 13 HER-2/neu and p53 negative patients (54%) are currently disease free (between one year to five years). In this sample of patients, the HER-2/neu oncogene is not overexpressed or amplified in osteosarcoma; six of 22 samples (27%) showed overexpression of p53 by IHC analysis. By FISH, none of the samples demonstrated deletion of p53. Neither HER2/neu nor p53 expression was important for the biology of osteosarcoma in this population.

Melanoma cells can tolerate high levels of transcriptionally active endogenous p53 but are sensitive to retrovirus-transduced p53

Malignant melanomas are frequently characterized by elevated levels of wild-type p53, suggesting that p53 function could be suppressed by a mechanism different from p53 mutation. We analysed the functionality of the p53-signaling pathway in a panel of seven human melanoma cell lines consisting of one p53-deficient line, two lines with mutant p53, and four lines expressing wild-type p53. Only lines with wild-type p53 were characterized by elevated levels of endogenous p21, high activity of p53-responsive reporters and accumulation of p53 in response to genotoxic stress, common properties of functional p53. The presence of wild-type p53 was associated with depletion or loss of p14ARF and p16 expression. The levels of p33ING1b and p24ING1c, two major products of Ing1 locus and putative coregulators of p53, were elevated in all cell lines tested; however, ectopic expression of either ING1 isoform had no effect on cell proliferation. All lines retained expression of Apaf-1, and all but one remained sensitive to ectopic expression of retrovirus-transduced p53. Our data indicate that regardless of abnormally high levels of p53 in melanomas, their p53 remains competent in transactivation of its targets, and, if highly overexpressed, capable of growth inhibition. Hence, the p53 pathway in malignant melanomas can be considered for pharmacological targeting and anticancer gene therapy.

Bcl-2 expression in metastatic malignant melanoma. Importance for the therapeutic efficacy of biochemotherapy

For the majority of patients with metastatic malignant melanoma the prognosis is poor. Immunotherapy and biochemotherapy have shown promise with a subset of durable responses, but there is still a great need for a better understanding of the mechanisms of action during treatment to optimize future treatment schedules. In the present study Bcl-2 expression was studied in biopsies from ten patients with metastatic malignant melanoma (five with regional disease and five with systemic disease) treated with biochemotherapy (cisplatinum 30 mg/m2 days 1-3, DTIC 250 mg/m2 days 1-3 i.v. and Interferon-alpha2b 10 MIU s.c. 3 days a week, on a 28-day cycle). The expression of Bcl-2 by the tumour cells was separately recorded in areas of histopathological regressive changes and in areas of unaffected tumour growth. Comparisons were made with biopsies from 14 untreated patients. In 10 of 10 treated patients a high expression of Bcl-2 by the tumour cells was found in areas of unaffected tumour growth. In contrast, only in 5 of 13 untreated patients was a high expression of Bcl-2 by the tumour cells found in these areas ( P=0.008). A significant difference was also found in the expression of Bcl-2 by the tumour cells between areas of unaffected tumour growth and areas of histopathological regressive changes ( P=0.03). The significantly higher expression of Bcl-2 by the tumour cells in areas of unaffected tumour growth in treated patients compared to untreated patients indicates that clones with a high expression of Bcl-2 may be present after therapy, preventing apoptosis and eventually in many patients resulting in progressive disease. Supporting this concept, a difference was also found between the expression of Bcl-2 in areas of unaffected tumour growth, i.e. in areas of treatment failure, and the expression in areas of histopathological regressive changes. Thus immunohistochemical analysis of tumour biopsies shortly after therapy seems to be a good surrogate endpoint that allows a detailed analysis of Bcl-2 expression. The high expression of Bcl-2 shown in unaffected tumour areas after therapy suggests the need for additional treatment, e.g. Bcl-2 antisense therapy.