Background Gastric adenocarcinoma (GAC) is the third deadliest malignant neoplasm worldwide, mostly because of late disease diagnosis, low chemotherapy response rates, and an overall lack of tumor biology understanding. Therefore, tools for prognosis and prediction of treatment response are needed. Quantification of circulating tumor cells (CTCs) and circulating tumor microemboli (CTM) and their expression of biomarkers has potential clinical relevance. Our aim was to evaluate CTCs and CTM and their expression of HER2 and plakoglobin in patients with nonmetastatic GAC, correlating the findings to clinicopathological data. Materials and Methods CTC enrichment was performed with isolation by size of epithelial tumor cells, and the analysis was performed with immunocytochemistry and microscopy. Two collections were made: one at diagnosis (55 samples before neoadjuvant treatment) and one after surgery and before adjuvant therapy (33 samples). Results A high detection rate of CTCs (90%) was observed at baseline. We evaluated HER2 expression in 45/55 biopsy samples and in 42/55 CTC samples, with an overlap of 36 subjects. Besides the good agreement observed for HER2 expression in primary tumors and paired CTCs for 36 cases (69.4%; κ = 0.272), the analysis of HER2 in CTCs showed higher positivity (43%) compared with primary tumors (11%); 3/5 patients with disease progression had HER2‐negative primary tumors but HER2‐positive CTCs. A significant CTC count drop in follow‐up was seen for CTC‐HER2‐positive cases (4.45 to 1.0 CTCs per mL) compared with CTC‐HER2‐negative cases (2.6 to 1.0 CTCs per mL). The same was observed for CTC‐plakoglobin‐positive cases (2.9 to 1.25 CTCs per mL). Conclusion CTC analysis, including their levels, plakoglobin, and HER2 expression, appears to be a promising tool in the understanding the biology and prognosis of GAC. Implications for Practice The analysis of circulating tumor cell levels from the blood of patients with gastric adenocarcinoma, before and after neoadjuvant treatment, is useful to better understand the behavior of the disease as well as the patients more likely to respond to treatment.

This is the first study to demonstrate the expression of EGFR protein in CTCs from sarcoma patients. It may open an area for future investigations. The next step is to characterize CTCs in a larger cohort of patients to better understand the role of EGFR in sustaining tumor metastasis in sarcomas.

The importance of recognizing osteogenic melanoma is based on difficulties for histologic recognition and its differentials diagnosis.

The classification of melanoma into four histological subtypes has been questioned regarding its clinical validity in providing relevant information for treatment for metastatic tumors. Specific genetic alterations are associated with particular clinical and histopathological features, suggesting that these could be helpful in refining existing melanoma classification schemes. We analyzed BRAF V600E mutated melanomas to explore the Reflectance confocal microscopy (RCM) utility as a screening aid in the evaluation of the most appropriate patients for genetic testing. Thus, 32 melanomas were assessed regarding their BRAF V600E mutational status. Experts blinded to dermoscopic images and V600E immunohistochemistry results evaluated RCM images regarding previously described melanoma features. BRAF positive melanomas were related to younger age (p = 0.035), invasive melanomas (p = 0.03) and to the presence of hiporreflective cells (p = 0.02), epidermal nests (p = 0.02), dermal-epidermal junction nests (p = 0.05), edged papillae (p = 0.05), and bright dots (p = 0.05), and to absence of junctional thickening due to isolated cells (p = 0.01) and meshwork (p = 0.02). This study can not characterize other mutations in the BRAF, because the immunohistochemistry is specific to the type V600E. The findings should encourage the genetic evaluation of BRAF mutation. This study highlights the potential of RCM as a supplementary tool in the screening of BRAF-mutated melanomas.

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557 Background: Germ-cells testicular tumors are the most common cancer in young males, usually curable in early stages. Therefore, only 25% of relapsed patients are long-term survivors. Previous non-randomized studies showed promising results with HDC, however, the only randomized trial did not support this approach. Here we report our experience in a Brazilian academic center Methods: We conducted a retrospective review of all consecutive patients treated with salvage HDC followed by Stem-Cell transplantation at our service (1996 – 2016). Survival curves were estimated by Kaplan-Maier method. Prognostic factors were determined by Cox regression model. Results: We found 36 eligible patients. The cohort median follow-up was 56 months (m). At 2 years 50.4% of the patients were alive, and 46.7% were disease-free. The median overall survival (OS) was not-reached and the median progression-free survival (PFS) was 21.8 m. The overall response-rate was 61.2% (22% had complete response and 39% had partial response). All patients who achieved complete response were alive at the last follow-up, and only one had progressive disease. Out of the patients who achieved partial response, one third were rescued with surgery (46% teratoma, 23% fibrosis, and 31% residual disease). Approximately 80% were alive in 2 years vs 20% not operated. Complete response (vs. others) and HDC as second line treatment (vs. 3rd and 4th) were good prognostic factors, (HR N/A; p 0,03, HR 0.19; CI: 0.04-0.88, p = 0.01 respectively). In 2 years, the OS in patients treated in 2nd line was approximately 80%, 50% for 3rd line, and 0% of those treated in 4th line. 89% of the patients experienced grade 3 toxicity, and 25% grade 4. The most common were neutropenic fever (69%), mucositis (36%) and diarrhea (25%). There were 3 deaths related to the treatment. Conclusions: Patients with complete response have sustained long-term survival, and represent the subgroup with evident benefit of the treatment. Surgery, when feasible, can rescue 80% of the patients with partial response. According to our data, we do not recommend this modality of treatment in 4th line.

525 Background: TKI have improved the prognosis of patients with mRCC, but rarely lead to durable response. Predictive clinical biomarkers have been studied in the last few years, but most are still controversial. Objective: Identify the role of the clinical and laboratorial biomarkers of prognosis and outcome in mRCC. Methods: A retrospective study with mRCC treated with VEGFR-TKi in first line at A C Camargo Cancer Center (Jan-07 to Apr-16). Studied biomarkers: induced hypertension (HTN), acquiried hypothyroidism, proteinuria, and neutrophil to lymphocyte ratio (NLR). Data were analized in relation to progression free survival (PFS), overall survival (OS), and objetive response rate (ORR) stratified by each marker. Results: We included 94 patients (76.6% sunitinib, 21.3% pazopanib, 2.1% sorafenib). Overall, ORR to VEGFR-TKI was 41.1%; clinical benefit rate was 82.1% (43% Stable disease). Median PFS was 11.4 months (mo)(CI 95% 8.7-14.1) and median OS was 32.1 mo(CI 95% 23.4-40.8). HTN was numerically associated with longer PFS (20.1 vs. 8.2 mo) and OS (37.2 vs. 28.2 mo), but not statistically significant. Only high level TSH (>10) was associated with significant longer PFS and OS, p=0.001 and p<0.001, respectively. There was no association between proteinuria and better outcome. Finally, NLR≥3 pre-treatment was independent prognostic factor, and NLR≥3 post treatment (12aweek) predicted poor OS (9.6 vs 33.9 mo). A “NLR conversion” (before ≥3, turn to <3) was associated with longer OS (28.2 vs. 11.6 mo, p=0.0012). Conclusions: TSH elevation is a good biomarker of better outcome in patients in treatment with TKI. NLR is an important inflamatory marker associated with shorter survival and NLR conversion can be an early biomarker of better outcome to mRCC patients in first line.

Colorectal cancer presents high incidences (9.7%) and mortality rates (8.5%) worldwide in men and women. Although the early detection of colon cancer promotes high cure rates (30-40%), there are still patients who experience local recurrence as well as distant metastases. The main treatment is surgery-based and then, after risk evaluation, patients can undergo or not undergo adjuvant chemotherapy. Circulating tumor cells (CTCs) and circulating tumor microemboli (CTM) seem to play an important role in these processes, being detached from tumor and circulating in blood vessels before surgery intervention. Our objective, therefore, was to evaluate the role of CTCs and CTM in stages I-III colon cancer patients. Here, we collected 10 mL of blood from presurgery colon cancer and filtrated the sample in ISET® (Isolation by Size of Epithelial Tumor cells) device. This study started on July 2016. CTCs counts were assessed and correlated with clinical and pathologic data. We included 15 patients. However, one patient was identified as metastatic after surgery and therefore excluded from these analyses. From 14 patients analyzed, 8 (57.1%) were male, with a median age of 65 years (53-87). The most prevalent cancer sites were right colon (n= 6;42.9%) and left colon (n=4;28.6%). CTCs detection rate was 85.7%, and the mean and median of CTCs were 5.1/mL and 2.6/mL, respectively (0-30.3/mL). We found CTM in 4/14 patients (28.5%). Histopathologic analysis showed that no patient had blood vessel invasion, 5 (35.7%) had lymphatic invasion, and 4 (28.6%) had perineural invasion. Four patients (28.4%) were classified as stage I and 10 (71.4%) were classified as stage II and III. From patients with RAS mutational analysis available (12), 9 (75%) presented tumor mutation. Although we present a limited sample, exact Fisher's test showed an association between lymphatic invasion and CTC number above the median (P= 0.03), and the presence of CTM was most frequent in this group of patients, although without statistical significance (P= 0.09). CTM absence was associated with pathologic T= 2 and 3 (P= 0.06), when compared to pathologic T= 4. Our next steps are to evaluate some proteins in CTCs that could confer an invasive phenotype, resistance to adjuvant treatment as well as verify the pattern of mutations in CTCs and CTMs. Moreover, this is the first study to show the efficacy of ISET method in detecting high rates of CTCs from stage I-III colon cancer patients. Citation Format: Emne Abdallah, Virgílio Silva, Bianca Flores, Alexcia Braun, Ana Urvanegia, Vanessa Alves, Marcello Fanelli, Samuel Aguiar, Ludmilla Chinen. Circulating tumor cell analysis in locally and advanced colon cancer: A pilot study [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; São Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr B06.