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This study aims to investigate the utility of digital protocols for Ki-67 immunohistochemistry quantitative analysis (“hot spot” method) in the setting of well-differentiated hepatocellular neoplasms. Resection cases of typical hepatic adenomas (HAs) (n = 40), atypical HAs (n = 9), and well-differentiated hepatocellular carcinomas (WD HCCs) (n = 56) were selected. HAs were further classified by immunohistochemistry using antibodies against liver fatty acid binding protein, glutamine synthetase, B-catenin, hepatic serum amyloid A, and C-reactive protein. Ki-67 proliferative index by immunohistochemistry was evaluated in all cases by digital analysis using a modified neuroendocrine tumor “hot spot” protocol. The proliferative rate of HAs (typical, median 1.2% (range 0–7.4%) and atypical, median 1.0% (range 0.3–3%)) was significantly lower than that of WD HCCs (median 4.5%, range 0–49.8%) (P

Context.— Pulmonary carcinoids are classified as typical or atypical by assessing necrosis and mitoses, which usually cannot be adequately assessed on small biopsies. Ki-67 is not currently used to grade pulmonary carcinoids, but it may be helpful to determine preliminary grade in biopsies. However, the rate at which Ki-67 could underestimate or overestimate grade on small biopsies has not been well studied. Objective.— To compare Ki-67 labeling obtained on small biopsies to subsequent resection. Design.— Ki-67 was performed on paired biopsy and resection specimens from 55 patients. Slides were scanned using Aperio ScanScope. Labeling index was determined using automated hot spot and tumor tracing methods. Results.— The study included 41 typical and 14 atypical carcinoids. Atypical carcinoids were larger and had more distant metastases. Death from disease occurred in 3 patients (all had atypical carcinoids). Median hot spot Ki-67 labeling index was greater in resection compared with biopsy by 0.7% (P = .02). Median tumor tracing Ki-67 was lower in resection compared with biopsy by 0.5% (P < .001). Receiver-operating characteristic analysis showed similar hot spot Ki-67 cutoffs to predict atypical histology (3.5% for biopsy, 3.6% for resection; area under the curve [AUC], 0.75 and 0.74, respectively). Different optimal cutoffs were needed for tracing method based on biopsy (2.1%; AUC, 0.75) compared with resection (1.0%; AUC, 0.67). Conclusions.— Hot spot Ki-67 tends to underestimate grade on small biopsies, whereas grade is overestimated by tumor tracing. Hot spot Ki-67 cutoff of 3.5% predicted atypical histology for both biopsy and resection. Different biopsy and resection cutoffs were necessary for tumor tracing, which would make clinical implementation more difficult.

Tumor cell proliferation rate determined by either Ki-67 index or mitotic count (MC) has shown to be a prognostic factor for gastrointestinal neuroendocrine tumors in general, and after its incorporation in the 2010 World Health Organization tumor grading system, it has become essentially mandatory in pathology reports for all gastrointestinal neuroendocrine tumors, regardless of tumor location. Nevertheless, clinical significance for the Ki-67 index or MC has not been well demonstrated in small intestinal neuroendocrine tumor (SINET), especially those without distant metastasis, the majority of which have very low proliferation rates. We assessed the clinical behavior of 130 SINETs in relation to stage, Ki-67 index, MC, and other pathologic features. Most SINETs (86%) were grade 1 and 14% were grade 2. There were no grade 3 tumors or poorly differentiated neuroendocrine carcinomas. On multivariate analysis, age, Ki-67 index >5%, MC >10/50 high-power field, stage IV, and liver metastases were associated with increased risk of death in all patients. When both stage and grade were considered, Ki-67 index >5% was associated with a nearly 4-fold increased risk of death in stage IV cases (n=60). In contrast, Ki-67 index did not show prognostic value for patients with stages I to III disease (n=70), although MC >1/50 high-power field was significantly associated with death on multivariable analysis. Our study confirms that liver metastasis and increased tumor cell proliferation rate are independent prognostic factors for SINETs, but shows that most SINETs have a very low proliferation rate, which limits its value for predicting tumor behavior. By combining staging and grading information, we demonstrate different roles and cutoff values of Ki-67 index and MC in SINET with different stages.

Introduction Vestibular schwannoma (VS) behavior following subtotal resection (STR) is highly variable. Overall progression rates have been reported as high as 44%, and optimal treatment is controversial. Correspondingly, identification of a reliable clinical or pathologic marker associated with progression after STR would help guide decision-making. Methods A prospectively maintained institutional VS registry from 1999 to 2014 was retrospectively reviewed for sporadic VS patients who underwent primary STR without preceding stereotactic radiosurgery (SRS) by a single neurosurgery-neurotology team. Primary endpoints included tumor progression and postoperative facial nerve function. Pathologic specimens were stained for Ki67, CD68, S100, and SOX10 and were quantitated by digital imaging analysis. Macrophage density was defined as the ratio of CD68+ macrophages to S100+ macrophages and Schwannian tumor cells. Clinical outcomes were correlated with pathologic markers. Results Forty-six patients met the study inclusion criteria. Thirteen (28%) progressed during a mean 57 months of follow-up (range 15–149). Favorable postoperative facial nerve function (House–Brackmann I–II) was achieved in 37 (80%). CD68+ cells were present at significantly higher concentrations in tumors that progressed (p = 0.03). Higher macrophage density was significantly associated with both tumor progression (p = 0.02) and unfavorable facial nerve function (p = 0.02). Ki67 percent positivity was not significantly associated with either primary endpoint (p = 0.83; p = 0.58). Conclusions Macrophage density may provide an important marker for individuals at the highest risk for progression of VS after STR, potentially prompting closer surveillance or consideration for upfront SRS following STR. This finding supports preceding conclusions that an intratumoral macrophage-predominant inflammatory response may be a marker for tumor growth and a potential therapeutic target.

e21039 Background: Tumor-infiltrating neutrophils (TINs) and their myeloid precursors play an important role in cancer biology. While activated neutrophils have been shown to kill tumor cells, there is growing evidence that neutrophils may also support tumor progression by impairing T cell-dependent anti-tumor immunity. We hypothesized that low TINs would be associated with better responses to immunotherapy (IO). Methods: Pretreatment biopsies from 15 metastatic melanoma (MM) pts treated with anti-CTL4 and anti-PD-1 therapy from 2012-17 were collected and stained with myeloperoxidase (MPO). Slides were scanned at 40x magnification on the Aperio ScanScope AT Turbo brightfield instrument (Leica Biosystems) at a resolution of 0.25 microns per pixel. To indicate the region of analysis, the digital pen tool was used to trace a minimum 85% of tumor. Ten fixed-sized boxes were placed on the hottest staining region in a second annotation layer on the image. The boxes equaled 1mm2 in total area. If the tumor tracing had an area of 1mm2, or less, boxes were not placed on the image. The selected tissue was analyzed using an Aperio imaging quatification algorithm . The number of 3+ cells were considered positive for neutrophils and used in subsequent calculations. Quality control review was performed on a subset of cases by Anatomic Pathologists. Response to therapy was assessed using the Response Evaluation Criteria In Solid Tumors (RECIST). Overall survival (OS) was calculated using the Kaplan Meier method. Results: The median number of treatment lines before the biopsy was 1 (range 0-2). The treatment immediately following the biopsy consisted of ipilimumab (n = 10, 66.6%), pembrolizumab (n = 4, 26.6%), ipilimumab/nivolumab (n = 1, 6.6%). The median number of neutrophils in the biopsy hotspot was 92/mm2 (range 6-219) for the entire cohort. For patients achieving PR and CR after 4 cycles of therapy, the median neutrophils were 36/mm2 (IQ 14-78) while the median was 106/mm2 (IQ 60-138) for patients who had progressive disease,( p = 0.04). There was no correlation between the numbers of neutrophils in the biopsy with the absolute neutrophil count in the peripheral blood (R value: 0.012). Conclusions: Decreased TINs are significantly associated with better responses to IO in MM pts. Measurements of TINs may help to select patients who are likely to benefit from anti-CTL4 and anti-PD-1 therapy. Additionally, exploration of whether combining therapies that decrease neutrophils intratumorally should be explored.