Comparison of PD-L1 tumor cell expression with 22C3, 28-8, and SP142 IHC assays across multiple tumor types.

BACKGROUND: Multiple PD-L1 immunohistochemistry (IHC) assays, including DAKO 22C3, DAKO 28-8, and Ventana SP142 PD-L1 IHC assays, have been approved by the Food and Drug Administration as a companion diagnostic (CDx) for various antiprogrammed death-1 and antiprogrammed death ligand 1 (PD-L1) based cancer immunotherapies. Here we present 22C3, 28-8, and SP142 analysis of 418 tumor specimens encountered in routine clinical practice. METHODS: All specimens were tested with 22C3, 28-8, and SP142 assays following the manufacturer's established staining protocols. RESULTS: The same PD-L1 status (defined as tumor cell expression (TC) scores with all three assays ≥1% or all <1%) was observed in 60.0% (251/418) tumor specimens (45.9% (192/418) were triple negative and 14.1% (59/418) were triple positive). A total of 54.1% (226/418) tumor cases were positive with at least one IHC assay (94.2% (213/226), 77.0% (174/226), and 28.8% (65/226) of these were positive for 22C3, 28-8 and SP142, respectively). Among the 40.0% (167/418) tumor cases that showed a different PD-L1 status, 62.3% (104/167) were 22C3+/28-8+/SP142-, and 28.7% (48/167) were 22C3+/28-8-/SP142-. The same PD-L1 status with all three antibody clones was observed in 48.7% (97/199) of NSCLC cases, and among these, 54.6% (53/97) were triple negative and 45.4% (44/97) triple positive. A total of 73.4% (146/199) NSCLC cases were positive with at least one IHC assay (95.2% (n=139/146), 82.2% (n=120/146), and 32.2% (n=47/146) were positive for 22C3, 28-8, and SP142, respectively). Among the 51.3% (102/199) NSCLC cases that showed a different status among the three IHC assays, 67.6% (69/102) were 22C3+/28-8+/SP142-, and 23.5% (24/102) were 22C3+/28-8-/SP142-. A total of 81.1% (43/53) lung squamous cell carcinoma, 72.1% (88/122) of lung adenocarcinoma, 69.6% (16/23) of non-small cell lung cancer (NSCLC) not otherwise specified (NOS), and 50.0% (4/8) of small cell lung carcinoma cases were positive with at least one IHC assay. CONCLUSIONS: Our data suggest that 22C3 is the most sensitive PD-L1 IHC assay for tumor cell expression, followed by 28-8 and in turn by SP-142. These findings represent an additional factor for clinical teams to consider when deciding which PD-L1 IHC assay (and in turn which CDx-associated PD-L1 based immunotherapy) is most appropriate for each individual patient.

Specific Histopathologic Features Aid in Distinguishing Diffuse-type Gastric Adenocarcinoma From Metastatic Lobular Breast Carcinoma.

Metastatic invasive lobular carcinoma (mILC) may masquerade as primary diffuse gastric adenocarcinoma (PDGA) by demonstrating significant clinical and pathologic overlap. Accurate distinction is of therapeutic and prognostic significance. On the basis of anecdotal cases of mILC that lacked estrogen receptor and/or GATA3 expression, we analyzed the cytoarchitectural features of 28 mILC and 44 PDGA specimens obtained from women to assess features that would help in this distinction and prompt ancillary work-up. In addition to performing an interobserver agreement analysis among 3 pathologists, we also evaluated SATB2 expression in this setting. Eighteen of 20 (90%) patients had a history of ILC. The mean interval between initial diagnosis of breast cancer and metastasis was 7.3 years (range: 1 to 36 y). Compared with mILC, PDGA was significantly associated with full-thickness mucosal involvement (47% vs. 80%; P=0.015), a nested/sheet-like growth pattern (32% vs. 68%; P=0.004), anastomosing cords (0% vs. 100%; P=0.001), multivacuolated cells (0% vs. 61%; P<0.0001), pleomorphic nuclei (4% vs. 70%; P<0.0001) and enlarged nuclei (4% vs. 70%; P<0.0001). Single file growth pattern (P<0.0001) and superficial lamina propria involvement (P=0.009) were more common in mILC. Estrogen receptor and GATA3 were expressed in all but 5 mILC cases; SATB2 was only seen in 30% of PDGA cases. Our results demonstrate that in a biopsy specimen, careful morphologic assessment can be extremely helpful in distinguishing mILC from PDGA and guiding ancillary work-up, especially when a history of breast cancer may not be readily available or when the neoplasm lacks expression of conventional breast markers.

Liver fibrosis during clinical ascertainment of glycogen storage disease type III: a need for improved and systematic monitoring.

PURPOSE: In glycogen storage disease type III (GSD III), liver aminotransferases tend to normalize with age giving an impression that hepatic manifestations improve with age. However, despite dietary treatment, long-term liver complications emerge. We present a GSD III liver natural history study in children to better understand changes in hepatic parameters with age. METHODS: We reviewed clinical, biochemical, histological, and radiological data in pediatric patients with GSD III, and performed a literature review of GSD III hepatic findings. RESULTS: Twenty-six patients (median age 12.5 years, range 2-22) with GSD IIIa (n = 23) and IIIb (n = 3) were enrolled in the study. Six of seven pediatric patients showed severe fibrosis on liver biopsy (median [range] age: 1.25 [0.75-7] years). Markers of liver injury (aminotransferases), dysfunction (cholesterol, triglycerides), and glycogen storage (glucose tetrasaccharide, Glc4) were elevated at an early age, and decreased significantly thereafter (p < 0.001). Creatine phosphokinase was also elevated with no significant correlation with age (p = 0.4). CONCLUSION: Liver fibrosis can occur at an early age, and may explain the decrease in aminotransferases and Glc4 with age. Our data outlines the need for systematic follow-up and specific biochemical and radiological tools to monitor the silent course of the liver disease process.

Low-Volume Lymph Node Metastases in Endometrial Carcinoma.

OBJECTIVE: The aim of this study was to determine the histopathologic characteristics of patients with endometrial carcinoma with low-volume metastases (micrometastases and isolated tumor cells) compared with macrometastases. METHODS: We performed a retrospective review of patients with endometrial carcinoma. RESULTS: Among 350 robotic-assisted hysterectomies for endometrial cancer, 187 (53%) underwent attempted sentinel lymph node (SLN) biopsy. At least 1 SLN was detected in 185, a 99% overall detection rate; 108 (58%) also had non-SLNs removed. Among 91 patients with SLNs and non-SLNs from the ipsilateral hemipelvis, both were negative in 74 (81%) and positive in 7 (8%), and 10 (11%) had a positive SLN with negative non-SLNs. Among 17 patients with SLNs and non-SLNs from the contralateral hemipelvis, both were negative in 12 (71%), both were positive in 3 (18%), and 2 patients (12%) had negative SLNs with contralateral positive non-SLNs. Among 79 patients with only a SLN dissection, 4 (5%) were positive; among 69 patients with only a non-SLN dissection, 14 (20%) had positive lymph nodes. Among 24 patients with metastatic SLNs, 9 (38%) had isolated tumor cells, 3 (13%) had micrometastases, and 12 (50%) had macrometastases. Among the 40 total patients with metastatic lymph nodes, low-volume metastases represented the largest metastatic deposit in one third of patients, all of which had SLN dissection. All 12 with low-volume metastases had endometrioid histology compared with less than half (46%) of those with macrometastases (P < 0.01). Grade 1 carcinoma was present in 7 (58%) of the patients with low-volume metastases compared with 4 (14%) of those with macrometastases (P < 0.01) Furthermore, significantly more patients with low-volume metastases versus macrometastases had less than 50% myometrial invasion (67% vs 4%, P < 0.001). CONCLUSIONS: Low-volume disease was present in one third of patients with nodal metastases, the largest metastatic deposit only in patients who had SLN dissection; these patients were significantly more likely to have grade 1 endometrioid carcinoma with less than 50% myometrial invasion, traditional "low-risk" features.

Rapid Antimicrobial Susceptibility Testing Using Forward Laser Light Scatter Technology.

The delayed reporting of antimicrobial susceptibility testing remains a limiting factor in clinical decision-making in the treatment of bacterial infection. This study evaluates the use of forward laser light scatter (FLLS) to measure bacterial growth for the early determination of antimicrobial susceptibility. Three isolates each (two clinical isolates and one reference strain) of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were tested in triplicate using two commercial antimicrobial testing systems, the Vitek2 and the MicroScan MIC panel, to challenge the BacterioScan FLLS. The BacterioScan FLLS showed a high degree of categorical concordance with the commercial methods. Pairwise comparison with each commercial system serving as a reference standard showed 88.9% agreement with MicroScan (two minor errors) and 72.2% agreement with Vitek (five minor errors). FLLS using the BacterioScan system shows promise as a novel method for the rapid and accurate determination of antimicrobial susceptibility.

The LAST guidelines in clinical practice: implementing recommendations for p16 use.

OBJECTIVES: To determine the impact of implementing p16 Lower Anogenital Squamous Terminology Standardization Project for HPV-Associated Lesions (LAST) guidelines, we compared p16 use and follow-up data before and after implementation of the guidelines. METHODS: We reviewed all cervical biopsy specimens diagnosed by two pathologists before and after implementation of the LAST guidelines and calculated the rate of and reason for p16 use across all biopsy specimens, high-grade squamous intraepithelial lesion (HSIL) detection, and follow-up. RESULTS: In total, 1,829 and 1,623 cervical biopsy specimens were reviewed in periods A and B, respectively. Overall p16 use increased from 2.8% to 6.2% (P < .001). Recommendations 2 and 4 increased from 0.16% and 0% of all cervical biopsy specimens in period A to 1.4% and 1.9% in period B, respectively (P < .0001). p16+ HSIL increased from 1.4% to 2.3% (P < .05). The positive predictive value of p16+ HSIL increased from 48% to 76% (P < .05). CONCLUSIONS: Implementation of the p16 LAST guidelines resulted in a significant increase in p16 use and a significant increase in the positive predictive value of p16+ HSIL.

Synergistic Interactions between Abeta, tau, and alpha-synuclein: acceleration of neuropathology and cognitive decline.

Alzheimer's disease (AD), the most prevalent age-related neurodegenerative disorder, is characterized pathologically by the accumulation of beta-amyloid (Abeta) plaques and tau-laden neurofibrillary tangles. Interestingly, up to 50% of AD cases exhibit a third prevalent neuropathology: the aggregation of alpha-synuclein into Lewy bodies. Importantly, the presence of Lewy body pathology in AD is associated with a more aggressive disease course and accelerated cognitive dysfunction. Thus, Abeta, tau, and alpha-synuclein may interact synergistically to promote the accumulation of each other. In this study, we used a genetic approach to generate a model that exhibits the combined pathologies of AD and dementia with Lewy bodies (DLB). To achieve this goal, we introduced a mutant human alpha-synuclein transgene into 3xTg-AD mice. As occurs in human disease, transgenic mice that develop both DLB and AD pathologies (DLB-AD mice) exhibit accelerated cognitive decline associated with a dramatic enhancement of Abeta, tau, and alpha-synuclein pathologies. Our findings also provide additional evidence that the accumulation of alpha-synuclein alone can significantly disrupt cognition. Together, our data support the notion that Abeta, tau, and alpha-synuclein interact in vivo to promote the aggregation and accumulation of each other and accelerate cognitive dysfunction.

Age-dependent sexual dimorphism in cognition and stress response in the 3xTg-AD mice.

We sought to determine if sex impacts the cognitive and neuropathological phenotype of the 3xTg-AD mice. We find that male and female 3xTg-AD mice show comparable impairments on Morris water maze (MWM) and inhibitory avoidance (IA) at 4 months. Shortly thereafter, however, the cognitive performance varies among the sexes, with females performing worse than males. These behavioral differences are not attributable to differences in Abeta or tau levels. The behavioral effect is transient as from 12 months onward, the disparity is no longer apparent. Because females perform worse than males on stressful tasks, we explored their corticosterone responses and find that young female 3xTg-AD mice show markedly heightened corticosterone response after 5 days of MWM training compared to age-matched male 3xTg-AD mice; this difference is no longer apparent in older mice. Thus, the enhanced corticosterone response of the young female mice likely underlies their poorer performance on stressful tasks.