Biomedical subjects

Marc D Pacifico

Publications and source records attributed to Marc D Pacifico.

7 recordsLinked to original sources

PubMed2006

CD44v3 levels in primary cutaneous melanoma are predictive of prognosis: assessment by the use of tissue microarray.

Despite the use of sentinel node biopsy techniques, the search continues for other strategies to improve the accuracy of estimating prognosis in melanoma patients. Various biomarkers have previously been studied for use in this role, but none has yet achieved acceptance in routine practice. We have applied the novel technology of tissue microarray for the high throughput screening of a cohort of 120 primary cutaneous melanoma specimens for expression of the transmembrane glycoprotein CD44, splice variant 3 (v3), which has previously been implicated in tumor progression. A highly significant correlation between CD44v3 expression and Breslow thickness, Clark's level and patient age was demonstrated (Spearman correlation p < 0.001). Regarding clinical outcome, CD44v3 expression was shown to be significantly associated with better outcome (chi(2) = 7.2219, p = 0.0072). Furthermore, subgroup analysis revealed a sequentially improved survival probability associated with the intensity of CD44v3 staining (chi(2) = 12.5162, p = 0.0058). Analysis in a Cox multivariate model, however, did not show CD44v3 to be independently predictive of prognosis. The implications of these findings are considered, and the use of CD44v3 as a potential prognostic marker or a target for therapeutic manipulation are discussed.

Adult↗

PubMed2005

nm23 as a prognostic marker in primary cutaneous melanoma: evaluation using tissue microarray in a patient group with long-term follow-up.

The accurate estimation of prognosis in patients with melanoma is of increasing importance with novel adjuvant therapies on the horizon. The current prediction of prognosis employs techniques involving sentinel lymph node biopsy, which carries an associated morbidity and is of little use in patients who develop direct distant metastases or direct in-transit metastases. New strategies or factors are therefore needed to improve the accuracy of determination of prognosis. nm23 is a putative metastasis suppressor; however, conflicting data exist as to its role in melanoma progression and its use as a potential prognostic marker. The purpose of this study was to use the technique of tissue microarray to study a cohort of melanoma patients with long-term follow-up data in order to ascertain its potential use as a prognostic marker. One hundred and twenty patients with primary cutaneous melanoma were included in the tissue microarray and a commercially available immunohistochemical marker for nm23 was used for protein detection. nm23 expression was strongly correlated with Clark's level (P<0.001), Breslow depth (P=0.002) and patient age (P=0.014). nm23 expression was significantly associated with a poor patient outcome (chi2=7.2219, P=0.0072). Further analysis revealed that the intensity of nm23 expression also correlated with patient outcome (chi2=11.3281, P=0.0035). However, on multivariate analysis, nm23 was shown not to be an independent marker of prognosis. The results of this study, when taken with the existing literature, suggest a role for nm23 in melanoma disease progression. However, its use as a prognostic marker in routine practice does not appear to be justified.

Adolescent↗

PubMed2005

Development of a tissue array for primary melanoma with long-term follow-up: discovering melanoma cell adhesion molecule as an important prognostic marker.

Refining current prognostic capability is essential for improving the management of melanoma. This study was undertaken to develop a tumor array for the rapid assessment of novel prognostic markers in a series of specimens from melanoma patients with 7- to 10-year follow-up. A melanoma database of 120 patients with archival specimens was created after histopathological review of original specimens. A tissue array was developed allowing 480 biopsy samples from the 120 primary melanoma specimens to be embedded into a single paraffin block. This was sectioned and stained for the adhesion marker melanoma cell adhesion molecule (MCAM); after further review, 76 of the 120 specimens were suitable for further analysis. The slides were assessed by two independent observers without previous knowledge of the clinical outcome for staining positivity and stain intensity. Assessment of association between MCAM and clinicopathological features was carried out using chi-squared analysis, and univariate and Cox multivariate analyses were performed on the data. There was a high correlation between MCAM intensity and both Clark's level and Breslow thickness (Spearman correlation p < 0.001 for both). The data revealed that MACM was a highly specific prognostic marker for survival in univariate analysis (chi2 = 18, p < 0.0001). Subgroup analysis by stratification of the staining intensity revealed a sequentially worsening survival with increasing staining intensity (chi2 = 22.33, p < 0.0001). Multivariate analysis of survival showed MCAM to be an independent prognostic marker more accurate than all other clinicopathological parameters (p < 0.0001), including the Breslow depth. Further analysis within only intermediate-thickness tumors showed MCAM intensity added further refinement to outcome prediction (chi2 = 22.33, p < 0.0001). The tissue array provided a rapid method of analyzing up to 480 specimens within a single paraffin block. This will benefit many areas of plastic surgery research. The identification of adhesion markers revealed a valuable prognostic marker for predicting outcome and a potential target for therapeutic manipulation.

Adult↗

PubMed2005

Identification of P-cadherin in primary melanoma using a tissue microarrayer: prognostic implications in a patient cohort with long-term follow up.

Sentinel lymph node biopsy is the most accurate technique for establishing melanoma patient prognosis but is associated with morbidity and is of little value in those tumors that first metastasize to sites other than the regional nodal basin. Noninvasive methods of establishing prognosis are therefore desirable. We have used the novel technology of tissue microarray to study a cohort of 120 patients with melanoma with long-term follow-up data for the expression of P-cadherin. The tissue microarray was successfully constructed and stained. Loss of P-cadherin expression was found to be significantly correlated with outcome (log rank chi2 = 10.1336, P = 0.0015). The results suggest a fundamental role for P-cadherin in melanoma progression and identify it as a potential prognostic marker and a possible target for therapeutic manipulation.

Adult↗

PubMed2004

Validation of tissue microarray for the immunohistochemical profiling of melanoma.

Tissue microarray technology allows high throughput profiling of cancer specimens by immunohistochemical staining. Protein expression varies throughout tumour specimens resulting in heterogeneous staining patterns, which has led to doubts as to the accuracy of tissue microarray. In an effort to validate the use of tissue microarray for melanoma immunohistochemical investigation, a study was conducted comparing the concordance of MCAM staining between whole tumour specimens and tissue microarray core biopsies. Data on full tissue sections were compared with the results of one to four 0.6 mm core biopsies per tumour on a tissue array. It was revealed that concordance of tissue array core biopsies in quadruplicate compared with full-section analysis for the expression and intensity of expression of MCAM.

Female↗

PubMed2003

Effect of imidazole on the solubility of a his-tagged antibody fragment.

A number of studies have demonstrated the limited solubility of single-chain Fv antibody fragments and its improvement by genetic engineering. This limits the stability of recombinant protein upon storage and the efficiency of chemical modification. The RAFT3 scFv used in the present work is specific for melanoma-associated proteoglycan and an attractive candidate for clinical radioimaging studies because of its unusual radiolabelling properties. However, when expressed with a c-terminal his(6) IMAC purification tag, the recombinant protein starts to precipitate after column elution and dialysis against PBS and reaches a concentration of soluble protein of approximately 150 microg/mL within a few days upon storage at 4 degrees C. We tested several commonly used buffer modifications (addition of detergents, high salt, amino acids) to improve the solubility and stability of the protein but without any major improvement. However, we found that, when the final dialysis step was omitted and the protein left in IMAC column elution buffer (PBS containing imidazole), it remained soluble. Furthermore, several months old and precipitated protein could be redissolved in this buffer without loss of antigen binding. This observation and the largely pH-independent nature of protein solubility suggest that neither salt bridges formed by the his(6) tail nor cross-linking of his(6) tails mediated by metal ions leached from the column during elution are responsible for the limited solubility of the protein in the absence of imidazole. The presence of imidazole did not interfere with radiolabelling and in vivo tumor targeting in a mouse model. The solubilizing and stabilizing effect of imidazole could be of use for his(6) tagged and poorly soluble recombinant proteins other than scFvs.

Animals↗

PubMed2003

Use of oncogene expression as an independent prognostic marker for primary melanoma.

For 25 years, the Breslow depth of primary tumors has remained the most accurate prognostic test of survival for primary melanoma. However a number of studies have indicated that outcome for intermediate-thickness melanomas (0.75-2.49 mm) is often at variance with that predicted by the Breslow depth. This study investigated c-myc oncogene expression in 92 primary tumors of intermediate thickness using flow cytometry. Oncoprotein expression was detected in 87 tumors (95%) with a median positivity of 48% (range, 0%-96%). Survival analysis performed using the Kaplan-Meier method revealed a significant association between oncoprotein positivity and clinical outcome (p < 0.01, log-rank test). Multifactorial analysis of survival using Cox's proportional hazards model revealed c-myc oncoprotein to be an independent prognostic marker more accurate than all other clinicopathological parameters including the Breslow depth (chi(2) = 9.68, p< 0.01). Estimation of c-myc oncoprotein is therefore recommended as a powerful prognostic marker for intermediate-thickness primary melanoma.

Biomarkers, Tumor↗