HRAS is mutated in B15% of Spitz nevi, and GNAQ or GNA11 is mutated in blue nevi (46-83% and B7% respectively). Epithelioid blue nevi and deep penetrating nevi show features of both blue nevi (intradermal location, pigmentation) and Spitz nevi (epithelioid morphology). Epithelioid blue nevi and deep penetrating nevi can also show overlapping features with melanoma, posing a diagnostic challenge. Although epithelioid blue nevi are considered blue nevic variants, no GNAQ or GNA11 mutations have been reported. Classification of deep penetrating nevi as blue nevic variants has also been proposed, however, no GNAQ or GNA11 mutations have been reported and none have been tested for HRAS mutations. To better characterize these tumors, we performed mutational analysis for GNAQ, GNA11, and HRAS, with blue nevi and Spitz nevi as controls. Within deep penetrating nevi, none demonstrated GNAQ or GNA11 mutations (0/38). However, 6% revealed HRAS mutation (2/32). Twenty percent of epithelioid blue nevi contained a GNAQ mutation (2/10), while none displayed GNA11 or HRAS mutation. Eighty-seven percent of blue nevi contained a GNAQ mutation (26/30), 4% a GNA11 mutation (1/28), and none an HRAS mutation. Within Spitz nevi, none demonstrated GNAQ or GNA11 mutations (0/30). Seventeen percent contained an HRAS mutation (5/30). All GNAQ and GNA11 mutations were p.Q209L (c.626A4T) point mutations, except 2 GNAQ mutations, which contained novel c.625_626CA4TT double mutations. Four HRAS mutations were in exon 2, and three in exon 3. This is the first study to identify HRAS mutations in deep penetrating nevi. The presence of HRAS mutations and absence of GNAQ or GNA11 mutations in deep penetrating nevi suggests classification of these unusual nevi within the Spitz nevus category of melanocytic tumors, rather than the blue nevus category. Modern Pathology (2013) 26, 1320-1328; doi:10.1038/modpathol.2013.77; published online 19 April 2013 Keywords: blue nevus; deep penetrating nevus; epithelioid blue nevus; GNA11; GNAQ; HRAS; spitz nevus Melanocytic nevi with epithelioid cytomorphology include epithelioid and spindle cell (Spitz) nevi, epithelioid blue nevi, and deep penetrating nevi. Deep penetrating nevus, a term first coined by Seab et al, 1 are unusual melanocytic neoplasms difficult to classify. Deep penetrating nevi are uncommon but are of importance due to their histological and clinical overlap with melanoma. They most commonly present on the extremities, followed by the head and neck and upper trunk. 2 The age range at presentation is wide; however, as with Spitz nevi, deep penetrating nevi most commonly present in younger patients (adolescence and young adults). They typically present as predominantly dermal to focally compound melanocytic proliferations with extension into the reticular dermis particularly along adnexal structures and neurovascular bundles, often extending into the subcutis. They tend to have a relatively symmetric wedge-shaped nodular growth pattern, although superficial variants can occur. 2 A plexiform disp...

5523 Background: Patients with p53 wildtype head and neck squamous cell carcinoma (HNSCC) tend to be HPV-positive, which associates with better prognosis. The purpose of this study was to explore biomarker expression profiles for insight into molecular differences in HNSCC patients based on p53 status. Methods: TP53 gene sequencing using the AmpliChip p53 microarray (Roche Molecular Systems, Inc.) was attempted on 61 HNSCC patients previously tested with Caris Target Now tumor profiling service. DNA was extracted from a FFPE sample, amplified and processed on the AmpliChip p53 microarray to detect single base pair substitution and deletion mutations in exons 2 - 11 and their flanking splice sites in the TP53 gene (GenBank X54156). EGFR FISH , HER2 IHC and 22 other predictive biomarkers, e.g. TS, TOPO2A, MGMT, etc., were assayed and retrospectively analyzed. All tests were performed in a CLIA-certified lab and interpreted by board-certified pathologists or cytogeneticists. Statistical analysis was performed using SPSS (PASW statistics17) for parametric and non-parametric tests of independence. Results: 52 cases provided sufficient quality DNA for p53 analysis and results revealed a mutation rate of 25% in HNSCC patients. Interestingly, only EGFR FISH and HER2 IHC (p=.002 and p=.004, respectively) were differentially expressed in wildtype vs. mutated p53. Matched-pair analysis in the p53 mutated subgroup (n=13) showed no significant trend regarding EGFR status (p=.763) but a slight trend towards HER-2 negativity (p=.020). In the p53 wildtype subgroup (n=39), a strong association with EGFR FISH non-amplification (n=28, 71.8%, p<.001) as well as HER-2 negativity (n=38, 97.4%, p<.001) was shown. Conclusions: To our knowledge, this is the first analysis of differential biomarker expression profiles in HNSCC based on p53 status. We hypothesize that the absence of EGFR amplification in the p53 wildtype cancers may be a contributing factor to the improved prognosis observed in HPV-positive HNSCC. Additionally, the strong association between p53 wildtype HNSCC patients and EGFR non-amplification suggests EGFR-targeted therapies like cetuximab would likely fail in p53 wildtype patients.

Exosomes are endosome-derived vesicles between 40-100 nm in diameter that are secreted by most cell types and can be distinguished from other types of microvesicles released from the cell by a characteristic protein composition. Furthermore, it is known that exosomes transport mRNAs, microRNAs (miRs) and proteins, all of which can be used to identify the cell from which they are derived and can be exploited for noninvasive molecular profiling. Differential expression of exosomal miRs between cancer and normal patient samples has been described previously. In this study we identified various exosome subpopulations by their particular surface protein topography. Subsequently, we characterized plasma-derived exosomal RNA content of each subpopulation for their specific association with a cancer phenotype. We have exploited the protein topography and RNA content of exosomes found in plasma from patients with cancer, benign prostatic hyperplasia (BPH), and unaffected individuals in order to characterize and identify the exosome subpopulations that are indicative of a given disease state. We intend to use the various biosignatures of these exosome subpopulations to develop a diagnostic platform to aid in the screening and diagnosis of various cancers. Using flow cytometry (FACS) and cell sorting techniques, we separated plasma-derived exosomes into protein-specific subpopulations by using membrane-specific protein biomarkers (e.g. EpCam). We consistently found that exosomes from prostate cancer (PCa) patients had the highest percentage of exosomes labeled with EpCam, PSMA and CD-9 compared to exosomes from normal, BPH and colorectal cancer (CRC) patients. Additionally, for each subpopulation of exosomes separated by FACS, we used quantitative expression profiling of miRs to identify expression signatures specific to cancer patients. We found that the RNA content of various subpopulations of exosomes, defined by their membrane protein biosignature, was unique. In an exosome subpopulation where proteins CD-9 and CD-81 are on the surface, miR 141 is significantly overexpressed in exosomes from PCa patient plasma compared to exosomes derived from normal plasma. Interestingly, miR 9 was significantly overexpressed in exosomes from BPH plasma in EpCam and PSMA exosomes but not in exosomes of the same subpopulation isolated from normal and PCa plasma, supporting the idea that exosome biosignatures can be used to distinguish between BPH and PCa. Additionally, miR 491 was overexpressed in EpCam expressing exosomes derived from colon cancer plasma compared to normal and PCa. These findings highlight the potential of exosome biosignature profiles for use as a diagnostic marker of disease and provide the foundation for a novel exosome-based diagnostic platform that can be used through a non-invasive blood test. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3018.

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