Evaluating mismatch repair deficiency for solid tumor immunotherapy eligibility: immunohistochemistry versus microsatellite molecular testing.

While many landmark solid tumor immunotherapy studies show clinical benefits for solid tumors with high microsatellite instability (MSI-H) and mismatch repair deficiency (dMMR), the methodologies focus only on confirmatory polymerase chain reaction (PCR) testing for MSI-H. Because some tumors are either dMMR or MSI-H but not the other, clinicians must choose between two testing methods for a broad patient population. We investigated the level of correlation between MMR protein immunohistochemistry (IHC) and microsatellite PCR testing results in 62 cancer patients. Thirty-five of the 62 cases (56.5%) were MSI-H by PCR, whereas 35 (56.5%) were dMMR by IHC. MMR IHC results correlated well with MSI PCR in 32 co-positive cases (91.4%) and 24 co-negative cases (88.9%). Six discrepant cases (9.7%) were identified, among which three were MSI-H and MMR intact, and three were dMMR and microsatellite stable. The results of this study highlight the implications of dMMR/MSI testing strategies on precision oncology. Co-testing with both MMR IHC and MSI PCR may be an effective screening strategy for evaluating immunotherapy eligibility status for solid tumors.

Molecular Characterization of Testicular Germ Cell Tumors Using Tissue Microdissection.

Testicular germ cell tumors are among the most common malignancies seen in children and young adults. Genomic studies have identified characteristic molecular profiles in testicular cancer, which are associated with histologic subtypes and may predict clinical behavior including treatment responses. Emerging molecular technologies analyzing tumor genomics, transcriptomics, and proteomics may now guide precision management of testicular tumors. Laser-assisted microdissection methods such as laser capture microdissection efficiently isolate selected tumor cells from routine pathology specimens, avoiding contamination from nontarget cell populations. Laser capture microdissection in combination with next generation sequencing makes precise high throughput genetic evaluation effective and efficient. The use of laser capture microdissection (LCM) for molecular testing may translate into great benefits for the clinical management of patients with testicular cancers. This review discusses application protocols for laser-assisted microdissection to investigate testicular germ cell tumors.

Morphologic and Immunohistochemical Characteristics of Fluorescent In Situ Hybridization Confirmed TFE3-Gene Fusion Associated Renal Cell Carcinoma: A Single Institutional Cohort.

TFE3-fusion associated renal cell carcinoma (TFE3-RCC) accounts for up to 5% adults and 40% of childhood RCC. Their comprehensive immunohistochemical (IHC) profile in correlation to fluorescence in situ hybridization (FISH) testing and their role in the diagnostic approach are not well documented because of lacking published data. FISH confirmed TFE3-RCC between years 2010 and 2020 were identified from institutional electronic database and retrospectively reviewed. Eighty-five TFE3-RCC were identified. Seventy-six of 85 (89.4%) TFE3-RCC cases had positive TFE3 expression, with diffuse and strong/moderate TFE3 expression in 45 (54.2%). Three (3.5%) TFE3-RCC had negative TFE3 expression whereas 6 (7%) cases had equivocal TFE3 expression. On the other hand, positive TFE3-IHC expression was observed in 17/29 (58.6%) TFE3-FISH negative RCC cases, although only 8 (27.5%) had diffuse and moderate/strong TFE3 expression. Diffuse and strong TFE3-IHC expression was statistically significant in predicting TFE3-FISH positivity (P<0.0001) regardless of morphologic features. After univariate and multivariate analyses, TFE3-IHC was the only parameter with significant predictive value for detecting positive TFE3-FISH (P<0.0001). On univariate analysis, sex, classic morphology, age, negative AE1/AE3 or cytokeratin 7 were not predictive of TFE3-FISH positivity. Diffuse and strong nuclear TFE3-IHC expression is significantly associated with TFE3-FISH positivity and can be used as a surrogate marker to confirm translocation associated cases. TFE3-rearranged RCCs show variable histomorphologic features and TFE3-FISH should be performed in cases presenting at a younger age or, regardless of the age, tumors with unusual morphology. Despite previous reports, negative pancytokeratin and positive cathepsin K expression may not be reliable markers for TFE3-RCC.

Paired Box 5 (PAX5) Expression in Poorly Differentiated Neuroendocrine Carcinoma of the Gastrointestinal and Pancreatobiliary Tract: Diagnostic and Potentially Therapeutic Implications.

Paired Box 5 (PAX5), a well-established B-cell marker, is preferentially expressed in small cell lung carcinoma and regulates the transcription of c-Met, offering a potential for therapeutic target. Its expression in poorly differentiated neuroendocrine carcinoma (PDNEC) of the digestive system has not been systemically evaluated. Archived pathology materials from 38 PDNEC in the gastrointestinal (GI) and pancreatobiliary (PB) tract were reviewed. Representative tumor sections were subject to immunohistochemical stain for PAX5, c-Met, and CD20. The extent of the staining [focal (<10%), patchy (10% to 50%), and diffuse (>50%)] and intensity (1+ to 3+) was evaluated. In total, 38 cases of well-differentiated neuroendocrine tumors from GI/PB tract served as controls. Nuclear PAX5 staining was observed in 16 (42%) cases in total, in 46% (11/24) of large cell neuroendocrine carcinoma, 67% (4/6) of small cell neuroendocrine carcinoma, and 13% (1/8) of mixed adenoneuroendocrine carcinoma, with diffuse (8), patchy (4), or focal (4) staining. The intensity was 3+ (2), 2+ (6), and 1+ (8). PAX5 expression was common in ampullary (4/5) and gastroesophageal junctional/esophageal (5/9) PDNEC. Two (5%) of 38 well-differentiated neuroendocrine tumors were positive for PAX5. Three PAX5 positive PDNEC showed weak cytoplasmic c-Met immunolabeling. CD20 was negative in all tumors. Our data show that PAX5 is commonly expressed in PDNEC of the GI/PB tract including small cell neuroendocrine carcinoma. This observation warrants a cautious approach when interpreting small biopsy of poorly differentiated neoplasms, especially when lymphoma is considered in the differentials. Further study of PAX5/c-Met signaling pathway and its potential therapeutic value in GI/PB PDNEC is warranted.

Hospital-acquired anemia due to diagnostic and therapy-related blood loss in inpatients with myasthenia gravis receiving therapeutic plasma exchange.

INTRODUCTION: Daily laboratory testing (DLT) is an important cause of iatrogenic anemia. Therapeutic plasma exchanges (TPE) represent another source of blood loss. This study investigated the contributions of DLT and TPE to changes in hemoglobin of inpatients with myasthenia gravis (MG) exacerbation. STUDY DESIGN AND METHODS: All admissions for MG that included TPE between 2008 and 2012 were identified. The DLT- and TPE-related blood losses per patient were estimated based on the number of laboratory tests and TPE procedures. The primary endpoint was the difference between the discharge hemoglobin (Hgb) and the admission Hgb (ΔHgb). Univariate and multivariable analyses were used to identify clinical predictors of ΔHgb. RESULTS: A total of 46 patients (52% male, average age of 58 years) had 90 hospitalizations and underwent 424 TPEs during the study-period. Their average length of stay (LOS) was 10.4 days, and total DLT and TPE-related blood losses were 107 and 94 mL, respectively. While 41% of patients were anemic on admission, 90% were anemic at discharge. The average ΔHgb was -2.2 g/dL. The patient's blood volume, renal function, admission number, LOS, and combined blood losses correlated with ΔHgb by linear regression, but only DLT was an independent predictor of ΔHgb in the multivariable analysis. CONCLUSION: Approximately 50% of MG patients admitted for TPE developed hospital-acquired anemia, which was directly correlated with the volume of blood collected for laboratory tests. A variety of strategies to reduce DLT could circumvent this iatrogenic complication.

Histopathological evidence of neoplastic progression of von Meyenburg complex to intrahepatic cholangiocarcinoma.

Von Meyenburg complex (VMC) is generally thought to be benign, although its preneoplastic potential for intrahepatic cholangiocarcinoma (iCC) has been a subject of contention. We retrospectively reviewed 86 hepatectomy specimens with a diagnosis of iCC. Morphologically, an association between iCC and VMC was appreciated in 35% of cases that illustrated a gradual neoplastic progression from benign VMC to dysplasia and then to iCC. Among them, 24 cases had VMC lined by epithelial cells with low-grade biliary dysplasia and 13 with high-grade biliary dysplasia. VMC-associated iCCs were smaller in size and well to moderately differentiated, with features of anastomosing glandular architecture, ductal carcinoma in situ-like growth pattern, peritumoral lymphocytic infiltrate, central fibrous scar, and complete pushing border. They often presented as T1 tumors. In contrast, non-VMC-associated iCCs were moderately to poorly differentiated with solid, cribriform or papillary growth patterns. They likely exhibited necrosis, perineural invasion, positive surgical margin, lymphovascular invasion, and high T stage. Additionally, Ki67 and p53 immunostains support the continuing neoplastic evolution from benign VMC to dysplasia and then to iCC. VMC could become neoplastic, serving as an in situ carcinoma lesion to transform to iCC. The underlying molecular alteration and clinical implication of this neoplastic transformation deserves further investigation.

Substantial hepatic necrosis is prognostic in fulminant liver failure.

AIM: To evaluate if any association existed between the extent of hepatic necrosis in initial liver biopsies and patient survival. METHODS: Thirty-seven patients with fulminant liver failure, whose liver biopsy exhibited substantial necrosis, were identified and included in the study. The histological and clinical data was then analyzed in order to assess the relationship between the extent of necrosis and patient survival, with and without liver transplantation. The patients were grouped based on the etiology of hepatic necrosis. Each of the etiology groups were then further stratified according to whether or not they had received a liver transplant post-index biopsy, and whether or not the patient survived. RESULTS: The core tissue length ranged from 5 to 44 mm with an average of 23 mm. Causes of necrosis included 14 autoimmune hepatitis, 10 drug induced liver injury (DILI), 9 hepatitis virus infection, and 4 unknown origin. Among them, 11 showed submassive (26%-75% of the parenchymal volume) and 26 massive (76%-100%) necrosis. Transplant-free survival was worse in patients with a higher extent of necrosis (40%, 71.4% and 100% in groups with necrosis of 76%-100%, 51%-75% and 26%-50%, respectively). Additionally, transplant-free survival rates were 66.7%, 57.1%, and 25.0% in groups of autoimmune hepatitis, DILI, and viral hepatitis, respectively. Even after liver transplantation, the survival rate in patients as a result of viral hepatitis remained the lowest (80%, 100%, and 40% in groups of autoimmune hepatitis, DILI, and viral hepatitis, respectively). CONCLUSION: Adequate liver biopsy with more than 75% necrosis is associated with significant transplant-free mortality that is critical in predicting survival.

Targeting the Programmed Cell Death-1 Pathway in Genitourinary Tumors: Current Progress and Future Perspectives.

BACKGROUND: Immune checkpoint inhibitors have revolutionized the treatment of many malignancies with over a dozen new United States Food and Drug Administration (FDA) approvals in the past six years. Due to the combination of potent treatment success and potentially deadly adverse effects from immune checkpoint inhibitors, gathering prognostic and predictive information about FDA-indicated tumors is prudent. METHOD: PD-L1 expression is a poor prognostic factor and predictive of better responses from both PD-1 and PD-L1 inhibitors in a variety of tumor types including Renal Cell Carcinoma (RCC) and urothelial carcinoma. Each FDAapproved PD-1/PD-L1 drug is paired with a PD-L1 Immunohistochemistry (IHC) assay. The majority of PD-1/PDL1 inhibitor clinical trials use proprietary IHC antibodies with undefined validation data. Thus, there is need for improved knowledge and application of PD-1/PD-L1 IHC biomarkers. There is a wealth of recent publications using antibody clones to characterize tumor PD-1/PD-L1 expression profiles. RESULTS: PD-1 is expressed on lymphocytes. PD-L1 is expressed on both tumor cells and immune cells. IHC staining appears in membranous fashion. A cutoff of at least 5% tumor cell PD-L1 staining for positivity has worked for most studies. Caution should be observed when employing tissue microarray techniques. CONCLUSION: RCC has been the most studied of the genitourinary malignancies for PD-L1 expression. The atezolizumab- approved IHC assay is unique in that only immune cell staining is quantified for the use of this assay in urothelial carcinoma. With familiarity of the current FDA guidelines, published medical literature, and general immunohistochemical considerations, the use of immune checkpoint biomarkers can continue to flourish.

Use of hydroxyethyl starch in leukocytapheresis procedures does not increase renal toxicity.

BACKGROUND: Hydroxyethyl starch (HES) is reportedly associated with an increased risk of renal failure and death when used for fluid resuscitation in critically ill patients. HES can be used during therapeutic leukocytapheresis (TL) procedures to enhance cell separation. The purpose of this study was to evaluate the occurrence of adverse events associated with HES during TL procedures. STUDY DESIGN AND METHODS: We performed a retrospective review of patients who underwent TL with and without HES in the period 2009 to 2013 at six academic medical institutions. RESULTS: A difference-in-difference regression analysis was used to estimate the mean change before and after TL in selected outcomes in the HES group relative to the average change in the non-HES group. Selected outcomes included serum creatinine, estimated glomerular filtration rate (eGFR), and white blood cell (WBC) count. A total of 195 patients who underwent 278 TL procedures were studied. We found no significant differences in serum creatinine levels and eGFR on Days 1 and 7 after TL procedure between patients who received and those who did not receive HES. The rate of adverse events and overall and early mortality were similar in both groups. Patients with acute myeloid leukemia who received HES had greater WBC reduction when HES was used. Additionally, patients who received HES had improvement in pulmonary leukostasis symptoms. CONCLUSION: HES, used at low doses during TL procedures, was not associated with adverse events previously ascribed to its use as a volume expander.

Establishing an institutional therapeutic apheresis registry.

Apheresis was first performed as a therapeutic procedure in the 1950s. The first national therapeutic apheresis (TA) registry was established in Canada in 1981 and other national registries followed, including two attempts at establishing an international TA registry. There is no national registry in the United States. Our large, academic, tertiary hospital has a very active TA service. We created a TA database to track all procedures performed by the apheresis service by transferring data from paper appointment logs and the electronic medical records into a Microsoft Access database. Retrospective data from each TA procedure performed at UAB from January 1, 2003 through December 31, 2012 were entered, including the type of procedure, indication, date, and patient demographics. Microsoft Excel was used for data analysis. During the 10-year period, our TA service treated 1,060 patients and performed 11,718 procedures. Of these patients, 70% received therapeutic plasma exchange (TPE), 21% received extracorporeal photopheresis (ECP), 4.5% received red cell exchange (RCE), 4.2% received leukocytapheresis, and 0.6% underwent platelet depletion. Among the procedures, 54% were TPEs, 44% were ECPs, 1.3% were RCEs, 0.5% were leukocytaphereses, and 0.1% were platelet depletions. According to the current literature, national and international TA use is underreported. We believe that the UAB TA registry provides useful information about TA practices in our region and can serve as a model for other institutions. Furthermore, data from multiple institutional registries can be used for clinical research to increase the available evidence for the role of TA in various conditions. J. Clin. Apheresis 31:516-522, 2016. © 2015 Wiley Periodicals, Inc.