Prognostic significance of molecular staging study of sentinel lymph nodes by reverse transcriptase-polymerase chain reaction for tyrosinase in melanoma patients.
ABSTRACT We performed this study to evaluate the clinical effect of microscopic and submicroscopic metastases in sentinel lymph nodes (SLNs) from patients with early-stage melanoma.
Patients with confirmed cutaneous melanoma (American Joint Committee on Cancer stages I and II) underwent standard lymphoscintigraphy and SLN biopsy. Serial sections were divided between routine histopathology with hematoxylin and eosin plus immunohistochemistry for HMB-45 and molecular analysis by nested reverse transcriptase-polymerase chain reaction (RT-PCR) assay for tyrosinase (using beta-actin as a control).
Of 180 patients analyzed (318 SLNs), 38 (21%) patients had positive SLN(s) by routine hematoxylin and eosin and immunohistochemistry (microscopic disease; group 1), and 142 (79%) had negative histological results. Analysis by RT-PCR detected tyrosinase in at least 1 SLN from 124 (69%) patients. Among patients with histologically negative SLN(s), tyrosinase was detected in 86 (48%) patients (submicroscopic disease; group 2), whereas 40 (22%) patients had negative results by both histology and RT-PCR (group 3). Sixteen (9%) patients had histologically negative SLNs and ambiguous RT-PCR results (group 4). Among 138 patients in the analysis of recurrence (mean follow-up, 45 months), only 18 patients had a recurrence: 11 (31%) of 35 in group 1, 5 (10%) of 51 in group 2, and 2 (5%) of 37 in group 3. No recurrences were seen in group 4. Only group 1 had a significantly shorter disease-free survival and overall survival compared with the other groups.
After a long follow-up period, molecular upstaging by tyrosinase RT-PCR failed to detect a subgroup of patients with an increased probability of recurrence.
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ABSTRACT: Tyrosinase inhibition studies are needed due to the medicinal applications such as hyperpigmentation. For probing effective inhibitors of tyrosinase, a combination of computational prediction and enzymatic assay via kinetics was important. We predicted the 3D structure of tyrosinase, used a docking algorithm to simulate binding between tyrosinase and phthalic acid (PA), and studied the reversible inhibition of tyrosinase by PA. PA inhibited tyrosinase in a mixed-type manner with a K(i) = 65.84 ± 1.10 mM. Measurements of intrinsic and ANS-binding fluorescences showed that PA induced changes in the active site structure via indirect binding. Simulation was successful (binding energies for Dock6.3 = -27.22 and AutoDock4.2 = -0.97 kcal/mol), suggesting that PA interacts with LEU73 residue that is predicted commonly by both programs. The present study suggested that the strategy of predicting tyrosinase inhibition based on hydroxyl groups and orientation may prove useful for screening of potential tyrosinase inhibitors.01/2011; 2011:294724. DOI:10.4061/2011/294724
Article: Idiosyncrasies of Scalp Melanoma[Show abstract] [Hide abstract]
ABSTRACT: Objectives/Hypothesis: Examine the accuracy of sentinel lymph node biopsy (SNB) in scalp melanoma (SM), patterns of nodal metastases, patient outcomes, and the utility of immunohistochemistry (IHC) in SNB evaluation.Study Design: Retrospective.Methods: There were 22 patients, 4 females and 18 males. Sentinel lymph nodes (SLN) were localized via preoperative lymphoscintigraphy, intraoperative gamma probe, and Lymphazurin injection. SLNs were stained with hematoxylin-eosin, S-100, HMB-45, Melan-A, micropthalmia transcription factor, and tyrosinase. SLNs were grouped into cervical (levels 1–5) and extracervical (parotid, suboccipital, retroauricular) regions.Results: There were 13 posterior and 9 anterior SMs. The first SNB were mapped to the extracervical regions in 77% of posterior and 78% of anterior lesions. SLN number ranged from 1 to 5. Ten patients had positive SLNs (PSLN). Forty percent of the PSLN group had SLNs mapped in both cervical and extracervical sites. Six underwent completion lymphadenectomy, with no additional positive nodes identified. No significant difference between PSLN and negative sentinel node (NSLN) patients was seen when compared by SLN number, Breslow's thickness, tumor ulceration, and clinical outcomes. Mean follow-up was 35 months. One patient died of disease. One isolated regional recurrence occurred. Sixty percent of PSLN and 92% of NSLN patients were recurrence free at last follow-up. One distant metastasis occurred in the NSLN group, and one local, one regional, and two patients with distant metastases were in the PSLN group at the time of last follow-up. Additional IHC did not detect other metastases in the NSLN group.Conclusions: SM is aggressive, as demonstrated by the high rate of SLN metastases, and there were no significant histopathologic factors in the primary tumor that predicted the presence of SLN metastases. SNB was accurate. The majority of first SLNs were localized in extracervical basins.The Laryngoscope 07/2007; 117(8):1354 - 1358. DOI:10.1097/mlg.0b013e31806146e5 · 2.03 Impact Factor
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ABSTRACT: To assess the prognostic value of sentinel lymph node biopsy status for patients with localized, clinically node negative, primary invasive cutaneous melanoma. Predictive value of positive or negative sentinel lymph node biopsy (SLNB) results for melanoma-related death, using raw numbers from informative publications. Setting and Reports comprising 50 patients with cutaneous melanoma who had undergone SLNB, based on PubMed search (January 1, 1993, through June 3, 2010). Melanoma-related death. For the 2 informative reports of patients with tumors of intermediate thickness (1-4 mm), risk of melanoma-related death ranged from 26.2% to 31.6% for node-positive cases and from 9.7% to 15.6% for node-negative cases. Based on 4 informative reports of patients with thin tumors (≤ 1 mm), risk of melanoma-related death ranged from 0% to 0.6% for both node-positive and node-negative cases. For the single informative report of patients with thick tumors (≥ 4 mm), risk of melanoma-related death was 32.5% for node-positive cases and 30.1% for node-negative cases. For 19 informative case series with any tumor thickness, risk of melanoma-related death ranged from 0% to 47.8% for node-positive cases and from 0% to 13.3% for node-negative cases. Prognostic information provided by SLNB status may be variably useful for patients who have tumors of intermediate thickness (1-4 mm) and not very useful for patients who have thin (≤ 1 mm) or thick (≥ 4 mm) tumors.Archives of dermatology 12/2010; 147(4):408-15. DOI:10.1001/archdermatol.2010.371 · 4.76 Impact Factor