Immunohistochemical detection of PD-L1 among diverse human neoplasms in a reference laboratory: observations based upon 62,896 cases.

Targeting of the PD1/PD-L1 immune checkpoint pathway has rapidly gained acceptance as a therapeutic strategy for a growing number of malignancies. Testing for expression of PD-L1 in tumor cells and immune cells has been used as a companion or complementary test for drugs targeting the PD1/PD-L1 pathway. We evaluated the results of PD-L1 testing in a large reference lab cohort. Using Food and Drug Administration-approved methods and interpretive instructions for each individual test, 62,896 cases were evaluated for PD-L1 using antibody clone 22C3, 28-8, SP142, or SP263. Case data analyzed included test results and information on tumor location and clinical history. No clinical outcome information was available and no attempt was made to correlate PD-L1 results with any other tests performed. The following numbers of cases were evaluated: 22C3 with tumor proportion score [n = 52585], 22C3 with combined positive score [n = 2631], 28-8 [n = 4191], SP142 [n = 850], and SP263 [n = 70]. In 22C3/tumor proportion score cases, the general results were as follows: negative 33.1% (n = 17,405), (low) expression 33.9% (n = 17,822), and high expression 29.5% (n = 15,486). In cases identified as metastatic, the results were as follows: negative 35.9% (n = 1411), (low) expression 30.8% (n = 1211), and high expression 30.7% (n = 1208). We found broad ranges of expression in tumor types with increasing positivity, as adenocarcinomas were reported as poorly differentiated, whereas squamous cell carcinomas showed more positivity as tumors were described as well-differentiated. The results of many individual tumor types were evaluated and showed, in general, high levels of positive expression. Practical challenges and observations of PD-L1 stain results and interpretation are also discussed.

A case of interdigitating dendritic cell sarcoma/histiocytic sarcoma--a diagnostic pitfall.

Interdigitating dendritic cell sarcoma (IDCS) and histiocytic sarcoma (HS) are two distinct rare hematolymphoid neoplasms, and HS derived from a likely pre-existing IDCS has never been reported in the English literature. Diagnosis of such entities in excised specimens is difficult, but becomes more difficult with the scant amount of materials obtained with fine needle aspiration (FNA) and core needle biopsy. Here we present an interesting and unique case of an IDCS located within a mesenteric mass, which was initially diagnosed as IDCS from the cytology of FNA and core needle biopsy specimens. After brief chemotherapy, the patient again developed abdominal pain, and a HS was diagnosed based on the excised segmental small intestinal specimen. While the exact relationship between the IDCS and HS cannot be ascertained, it is most likely that the HS is derived from the IDCS, although co-existing HS in addition to IDCS from the cytology specimen cannot be completely ruled out.

Primary intraocular lymphoma: a review.

Primary intraocular lymphoma (PIOL) is a rare, non-Hodgkin lymphoma considered to be a subtype of primary central nervous system lymphoma. We describe a 65-year-old woman who presented to the Hematology/Oncology Clinic at Scripps Clinic, La Jolla, California, who was diagnosed with bilateral PIOL without systemic disease. She enjoyed a 16-month remission but ultimately recurred in the brain. We reviewed the literature and present a discussion of the diagnostic criteria for PIOL and current strategies for treating PIOL in immunocompetent patients.

Serial sampling of ST2 predicts 90-day mortality following destabilized heart failure.

BACKGROUND: To prospectively determine the prognostic utility of serial sampling of the interleukin-1 receptor family member, ST2, for predicting 90-day mortality in patients with heart failure (HF) admitted to a Veteran Affairs Medical Center. METHODS AND RESULTS: A total 150 patients hospitalized with acutely destabilized HF were followed at the Veteran Affairs Healthcare System in San Diego, CA. Multiple cardiac-related parameters were measured including ST2, B-type natriuretic peptide (BNP), NT-proBNP, and blood urea nitrogen (BUN). Plasma samples were collected at 6 time points between admission and discharge. Biomarker concentrations were correlated to survival at 90 days. Uni- and multivariate analyses were used to identify prognostic variables. From admission to discharge, percent change in ST2 was strongly predictive of 90-day mortality: those patients whose ST2 values decreased by 15.5% or more during the study period had a 7% chance of death, whereas patients whose ST2 levels failed to decrease by 15.5% in this time interval had a 33% chance of dying. CONCLUSIONS: Percent change in ST2 concentrations during acute HF treatment is predictive of 90-day mortality and was independent of BNP or NT-proBNP levels. ST2 may provide clinicians with an additional tool for guiding treatment in patients with acute destabilized HF.