Doina Ivan

Activity of dasatinib against L576P KIT mutant melanoma: Molecular, cellular, and clinical correlates

Point mutations in the KIT receptor tyrosine kinase gene have recently been identified in mucosal, acral lentiginous, and chronically sun-damaged melanomas. We have identified the first human melanoma cell line with an endogenous L576P mutation, the most common KIT mutation in melanoma (∼30-40%). In vitro testing showed that the cell viability of the L576P mutant cell line was not reduced by imatinib, nilotinib, or sorafenib small molecule KIT inhibitors effective in nonmelanoma cells with other KIT mutations. However, the viability of the mutant cells was reduced by dasatinib at concentrations as low as 10 nM (P = 0.004). Molecular modeling studies found that the L576P mutation induces structural changes in KIT that reduce the affinity for imatinib (ΔΔGbind = −2.52 kcal/mol) but not for dasatinib (ΔΔGbind = +0.32 kcal/mol). Two metastatic melanoma patients with the L576P KIT mutation were treated with dasatinib, including one patient previously treated with imatinib. Both patients had marked reduction (>50%) and elimination of tumor F18-fluorodeoxyglucose (FDG)-avidity by positron emission tomography (PET) imaging after dasatinib treatment. These data support the selective inhibitory effect of dasatinib against cells harboring the most common KIT mutation in melanoma, and thus has therapeutic implications for acrallentiginous, chronic sun-damaged, and mucosal melanomas. [Mol Cancer Ther 2009;8(8):2079–85]

Correlation between KIT expression and KIT mutation in melanoma: a study of 173 cases with emphasis on the acral-lentiginous/mucosal type

The role of immunohistochemistry in the assessment of KIT status in melanomas, especially acral lentiginous/mucosal, is not well established. Although the reported prevalence of KIT mutations in acral lentiginous/mucosal melanomas is relatively low, detection of mutations in KIT can have profound therapeutic implications. We evaluated the efficacy of immunohistochemistry to predict mutations in KIT. One hundred seventy-three tumors, comprising primary and metastatic melanomas (141 acral lentiginous/mucosal, 5 nodular, 4 lentigo maligna, 3 superficial spreading, 2 uveal, 1 melanoma of soft parts, 8 metastases from unclassified primaries, and 9 metastases from unknown primaries) were studied. Immunohistochemical expression of KIT using an anti-CD117 antibody and KIT mutational analysis by gene sequencing of exons 11, 13, and 17 were performed. Eighty-one percent of acral lentiginous/mucosal melanomas, primary and metastatic, showed KIT expression by at least 5% of the tumor cells. The overall frequency of activating KIT gene mutations in acral lentiginous/mucosal melanomas was 15% (14 out of 91 cases), being the L576P mutation in exon 11 the most frequently detected (4 of 14 cases). Cases showing less than 10% positive tumor cells were negative for KIT mutations. Eighty-two percent (12 of 14) of cases positive for KIT mutation showed KIT expression in more than 50% of the cells. An association between immunohistochemical expression of KIT and mutation status was found (P=0.007). Immunohistochemical expression of KIT in less than 10% of the cells of the invasive component of acral lentiginous/mucosal melanomas appears to be a strong negative predictor of KIT mutation and therefore can potentially be used to triage cases for additional KIT genotyping.

Accuracy of core needle biopsy diagnosis in assessing papillary breast lesions: Histologic predictors of malignancy

The purpose of this study was to determine the accuracy of core needle biopsy (CNB) diagnosis of papillary breast lesions and to identify histologic features that can predict malignancy. We retrospectively reviewed 2876 CNB performed at MD Anderson Cancer Center (01/95–08/02) and identified 50 papillary lesions: 30 papillomas, eight atypical papillomas and 12 papillary carcinomas. Histopathological parameters were evaluated and radiographic findings were reviewed. When available, the CNB was compared with the excisional biopsy (EB) material. Carcinoma was confirmed by EB in 11/12 cases and invasion was correctly assessed in 67% of them. In EB, 6/8 (75%) atypical papillomas revealed carcinoma in situ or atypia and the remaining two (25%) were benign, six out of 30 (20%) papillomas had been excised and none had shown atypia; the remaining patients had clinical and radiological follow-up with no evidence of disease progression. We conclude that CNB is effective for assessing papillary breast lesions and that EB is more accurate in determining invasion. Cellular monotony, lack of myoepithelial cells, and cytologic atypia are more accurate predictors of malignancy (P<0.0001) than is the presence of mitoses (P<0.053). A diagnosis of carcinoma or atypical papilloma by CNB should warrant an EB, whereas benign papillomas may be followed if imaging findings are concordant.

Use of p63 expression in distinguishing primary and metastatic cutaneous adnexal neoplasms from metastatic adenocarcinoma to skin

Absract:  p63, a recently identified homologue of the p53 gene, is mainly expressed by basal and myoepithelial cells in skin. Others and we have shown the value of p63 in distinguishing primary adnexal tumors from visceral adenocarcinomas metastatic to skin. We now investigate the pattern of p63 expression in metastases from skin adnexal carcinomas and their cognate primaries and evaluate p63 expression in a larger case series of malignant cutaneous adnexal neoplasms. Immunohistochemical analysis for p63 was performed on 13 metastases of adnexal carcinomas and their corresponding primary tumors. Twenty visceral metastatic adenocarcinomas to the skin and 7 primary mucinous carcinomas with cutaneous or visceral origin were compared. The majority (90.9%) of primary adnexal tumors strongly expressed p63 and their metastases labeled similar to their cognate primary tumors. With one exception, primary or metastatic mucinous carcinomas did not express p63. Metastases from two apocrine carcinomas lacked p63 expression. All other cutaneous metastases from internal adenocarcinomas were negative for p63. Analysis of p63 expression may assist in the differential diagnosis of primary adnexal carcinomas versus metastatic visceral adenocarcinomas to the skin. Metastases from adnexal carcinomas generally retain p63 expression similar to their associated primary tumors.

Expression of p63 in primary cutaneous adnexal neoplasms and adenocarcinoma metastatic to the skin

p63, a recently identified homologue of the p53 gene, has been reported to be essential in the development of epithelia and is mainly expressed by basal and myoepithelial cells. The purpose of this study was to investigate the pattern of p63 expression in cutaneous adnexal neoplasms and to assess its possible value in the differential diagnosis of primary cutaneous neoplasms vs adenocarcinomas metastatic to the skin. Immunohistochemical analysis for p63 was performed on formalin-fixed, paraffin-embedded archival tissue from 20 benign adnexal tumors, 10 malignant adnexal tumors and 14 adenocarcinomas metastatic to the skin. The expression of p63 was evaluated in epidermal cells, skin appendages and metastatic tumor cells. p63 was consistently expressed in the basal and suprabasal cells of epidermis and cutaneous appendages, including the basal/myoepithelial cells of sweat glands. Out of 20 benign adnexal tumors, 13 (65%) showed strong (score 3) p63 expression; the remaining seven (35%) cases had score 2. All primary cutaneous carcinomas, including adenocarcinomas, expressed p63. In contrast, none of the metastatic adenocarcinomas to the skin was positive for p63 (P<0.001). Based on our findings, analysis of p63 expression may help in the differential diagnosis of primary vs metastatic cutaneous adenocarcinomas.

Adipophilin expression in sebaceous tumors and other cutaneous lesions with clear cell histology: an immunohistochemical study of 117 cases

Adipophilin is a monoclonal antibody against a protein on the surface of intracellular lipid droplets, and it was recently shown to be expressed in sebocytes and sebaceous lesions. This study examines adipophilin expression in various sebaceous lesions and other cutaneous tumors with a clear cell histology that may mimic sebaceous differentiation. A total of 117 cutaneous clear cell lesions including 16 sebaceous adenomas, 25 sebaceous carcinomas, 8 basal cell carcinomas, 12 squamous cell carcinomas, 6 xanthomas, 10 xanthelasmas, 10 xanthogranulomas, 4 balloon cell nevi, 5 trichilemmomas, 8 clear cell hidradenomas, and 13 metastatic renal cell carcinomas were examined using immunohistochemistry for the expression of adipophilin. Of these 117 lesions, 42 (36%) were from the periocular region. Adipophilin was expressed in 16 of 16 (100%) sebaceous adenomas, 23 of 25 (92%) sebaceous carcinomas, 10 of 10 (100%) xanthelasmas, 9 of 10 (90%) xanthogranulomas, 6 of 6 (100%) xanthomas, and 9 of 13 (62.5%) metastatic renal cell carcinomas. The characteristic staining pattern differed between sebaceous and non-sebaceous tumors with the former showing a membranous vesicular pattern and the latter being more granular. Adipophilin expression was not seen in any of the other lesions with clear cell histology, basal cell carcinomas, or squamous cell carcinomas, including cases that had focal clear cell differentiation. Adipophilin can be valuable in an immunohistochemical panel when evaluating cutaneous lesions with clear cell histology as it identifies intracytoplasmic lipid vesicles in sebaceous and xanthomatous lesions. In periocular lesions, it is effective in helping to exclude basal cell carcinoma and squamous cell carcinoma when sebaceous carcinoma is under consideration. Adipophilin expression is not as useful for the differential diagnosis that includes metastatic renal cell carcinoma, a rare but important, diagnostic differential. The pattern of adipophilin reactivity is important to observe as membranous vesicular staining is suggestive of intracellular lipids whereas granular cytoplasmic reactivity is not.

Cutaneous γδ T-cell lymphomas: a spectrum of presentations with overlap with other cytotoxic lymphomas.

We reviewed our multicenter experience with gamma-delta (&ggr;&dgr;) T-cell lymphomas first presenting in the skin. Fifty-three subjects with a median age of 61 years (range, 25 to 91 y) were diagnosed with this disorder. The median duration of the skin lesions at presentation was 1.25 years (range, 1 mo to 20 y). The most common presentation was deep plaques (38 cases) often resembling a panniculitis, followed by patches resembling psoriasis or mycosis fungoides (10 cases). These lesions tended to ulcerate overtime (27 cases). Single lesions or localized areas of involvement resembling cellulitis or pyoderma were reported in 8 cases. The most common anatomic site of involvement was the legs (40 cases), followed by the torso (30 cases) and arms (28 cases). Constitutional symptoms were reported in 54% (25/46) of the patients, including some with limited skin involvement. Significant comorbidities included autoimmunity (12 cases), other lymphoproliferative disorders (5 cases), internal carcinomas (4 cases), and viral hepatitis (2 cases). Lymphadenopathy (3/42 cases) and bone marrow involvement (5/28 cases) were uncommon, but serum lactose dehydrogenase (LDH) was elevated in 55% (22/39) of the patients. Abnormal positron emission tomography and/or computed tomography scans in 20/37 subjects mostly highlighted soft tissue or lymph nodes. Disease progression was associated with extensive ulcerated lesions resulting in 27 deaths including complications of hemophagocytic syndrome (4) and cerebral nervous system involvement (3). Median survival time from diagnosis was 31 months. Skin biopsies varied from a pagetoid pattern to purely dermal or panniculitic infiltrates composed of intermediate-sized lymphocytes with tissue evidence of cytotoxicity. The most common immunophenotype was CD3+/CD4−/CD5−/CD8−/BF1−/&ggr;-M1+/TIA-1+/granzyme-B+/CD45RA−/CD7−, and 4 cases were Epstein-Barr virus positive. This is the largest study to date of cutaneous &ggr;&dgr; T-cell lymphomas and demonstrates a variety of clinical and pathologic presentations with a predictable poor outcome.

Immunohistochemical detection of lymphovascular invasion with D2-40 in melanoma correlates with sentinel lymph node status, metastasis and survival

Using immunohistochemistry with anti‐D2‐40 for the detection of lymphovascular invasion (LVI‐IHC) in 74 cases of invasive melanoma, we found LVI in 23% (16/74) of the tumors. Data on sentinel lymph node (SLN) biopsy were available for 36 patients. Sixty‐seven percent (6/9) of patients with LVI‐IHC and 19% (5/27) without LVI‐IHC had positive SLN. Follow‐up data were available for 60 patients. Data on recurrence/metastasis were available for 60 patients. Twenty‐five percent (15/60) had LVI with immunohistochemistry. Fifty‐three percent (8/15) of these patients had “distant” metastasis or regional recurrence compared with 11% (5/45) in those without LVI‐IHC. Overall and disease‐specific survival was shorter for patients with LVI. In both the univariate and multivariate Cox proportional hazards regression models, LVI‐IHC in addition to ulceration was statistically significant with respect to overall survival. Specifically, in the reduced multivariate model, compared with patients with no LVI, patients with intratumoral LVI had a hazard ratio (HR) of 5.4 (95% CI 1.6–18.4), while patients with peritumoral LVI had a HR of 3.8 (95% CI 0.7–20.9). In addition, patients with ulceration had an increased hazard of 4.4 (95% CI 1.2–16.8).

Beyond BRAFV600: Clinical Mutation Panel Testing by Next-Generation Sequencing in Advanced Melanoma

The management of melanoma has evolved due to improved understanding of its molecular drivers. To augment the current understanding of the prevalence, patterns, and associations of mutations in this disease, the results of clinical testing of 699 advanced melanoma patients using a pan-cancer next generation sequencing (NGS) panel of hotspot regions in 46 genes were reviewed. Mutations were identified in 43 of the 46 genes on the panel. The most common mutations were BRAFV600 (36%), NRAS (21%), TP53 (16%), BRAFNon-V600 (6%), and KIT (4%). Approximately one-third of melanomas had >1 mutation detected, and the number of mutations per tumor was associated with melanoma subtype. Concurrent TP53 mutations were the most frequent event in tumors with BRAFV600 and NRAS mutations. Melanomas with BRAFNon-V600 mutations frequently harbored concurrent NRAS mutations (18%), which were rare in tumors with BRAFV600 mutations (1.6%). The prevalence of BRAFV600 and KIT mutations were significantly associated with melanoma subtypes, and BRAFV600 and TP53 mutations were significantly associated with cutaneous primary tumor location. Multiple potential therapeutic targets were identified in metastatic unknown primary and cutaneous melanomas that lacked BRAFV600 and NRAS mutations. These results enrich our understanding of the patterns and clinical associations of oncogenic mutations in melanoma.

Sentinel Lymph Node Biopsy for Ocular Adnexal Melanoma: Experience in 30 Patients

PURPOSE To report the findings on sentinel lymph node biopsy (SLNB) in 30 patients with ocular adnexal (conjunctival or eyelid) melanomas. DESIGN Prospective nonrandomized clinical trial. PARTICIPANTS Thirty patients with diagnosis of eyelid or conjunctival melanoma. METHODS All patients with ocular adnexal melanoma who underwent SLNB at The University of Texas MD Anderson Cancer Center between December 2000 and July 2008 are the subject of this report. Sentinel lymph node biopsy was performed as previously described by our group, and patients were prospectively followed up. MAIN OUTCOME MEASURES Findings on preoperative lymphoscintigraphy, SLNB, histopathologic examination of the primary tumor and sentinel lymph nodes (SNL), and nodal recurrence after SLNB. RESULTS Tumor sites were as follows: bulbar conjunctiva only, 14 patients; palpebral conjunctiva only, 8 patients; both bulbar and palpebral conjunctiva, 4 patients; and eyelid skin only, 4 patients. At least 1 SLN was identified in all patients. The median number of SLNs removed was 2 (range, 1-5). The most common basin sampled was the intraparotid (16 patients), followed by submandibular (level I) (11 patients), preauricular (9 patients), and superior cervical (level II) (6 patients). Five patients had SLN metastasis. Among the 25 patients with negative SLNB findings, there were 2 false-negative events. There were no false-negative events among patients treated during the last 4.5 years of the study. The mean Breslow thickness was 2.57 mm (range, 0.62-12 mm) among patients with negative SLNB and 4.86 mm (range, 2.0-7.2 mm) among patients with positive SLNB findings (P = 0.055). Ulceration was present in 11 patients (39%): 4 (80%) of 5 patients with positive SLNB and 7 (28%) of 25 with negative SLNB, including both patients with false-negative results. The median time from SLNB to last contact was 2 years (range, 10 months to 6 years). CONCLUSIONS Sentinel lymph node biopsy is effective for identifying nodal micrometastasis in patients with ocular adnexal melanoma and provides important prognostic information. The false-negative event rate in our series improved in the last 4 years, most likely because of a better technique and better patient selection for SLNB. We recommend consideration of SLNB for patients with intermediate-thickness ocular adnexal melanoma and those with ulceration.