A Novel BCMA Immunohistochemistry Assay Reveals a Heterogenous and Dynamic BCMA Expression Profile in Multiple Myeloma.

B-cell maturation antigen (BCMA) is a promising target for the treatment of multiple myeloma (MM) because the expression of this protein is largely limited to B-cell sets, plasma cells, MM, and other B-cell malignancies. Early studies assessing BCMA protein expression and localization have used insufficiently qualified immunohistochemistry assays, which have reported broad ranges of BCMA expression. As a result, our understanding of BCMA tissue expression derived from these data is limited, specifically the prevalence of BCMA expression on the cell surface/membrane, which has mechanistic relevance to the antimyeloma activity of several novel biotherapeutics. Here, we report on the qualification and application of a novel anti-BCMA immunohistochemistry antibody, 805G12. This antibody shows robust detection of BCMA in formalin-fixed, decalcified bone marrow tissue and provides key insights into membrane BCMA expression. The clone 805G12, which was raised against an intracellular C-terminal domain peptide of membrane BCMA, exhibited increased sensitivity and superior specificity across healthy and diseased tissue compared with the frequently referenced commercial reagent AF193. The new clone also demonstrated a broad range of expression of BCMA in MM and diffuse large B-cell lymphoma specimens. Additionally, cross-reactivity with closely related tumor necrosis factor receptor family members was observed with AF193 but not with 805G12. Furthermore, via established 805G12 and other independent BCMA assays, it was concluded that proteolytic processing by γ-secretase contributes to the levels of BCMA localized to the plasma membrane. As BCMA-directed therapeutics emerge to address the need for more effective treatment in the relapsed or refractory MM disease setting, the implementation of a qualified assay would ensure that reliable and consistent data on BCMA surface expression are used to inform clinical trial decisions and patient responses.

Megakaryocytes, erythropoietic and granulopoietic cells express CAL2 antibody in myeloproliferative neoplasms carrying CALR gene mutations.

Testing for the CALR mutation is included in the updated WHO criteria for essential thrombocythaemia (ET) and primary myelofibrosis (PMF). We report on the application of the CAL2 monoclonal antibody, raised against the mutated CALR gene to myeloid cases. The immunostain was used on 116 acute myeloid leukaemias (AML) and 66 myeloproliferative neoplasms (MPN) or myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN). None of AML cases was stained by the CAL2 antibody, while 20/66 MPNs and MDS/MPNs appeared positive. Fourteen of the latter cases were studied by molecular techniques, and all showed aberrations of the CALR gene. In addition, CAL2 positivity was found in some small-sized elements besides megakaryocytes. By double staining, these elements corresponded to small megakaryocytes as well as both erythroid and myeloid precursors. This finding suggests possible occurrence of CALR gene abnormalities in a stem cell.

Concordance among four commercially available, validated programmed cell death ligand-1 assays in urothelial carcinoma.

BACKGROUND: Antibodies targeting the programmed cell death-1 (PD-1)/PD-ligand 1 (PD-1/PD-L1) checkpoint have shown promising clinical activity in patients with advanced urothelial carcinoma (UC). Expression of PD-L1 in UC tumors has been investigated using different antibody clones, staining protocols, and scoring algorithms. The aim was to establish the extent of concordance among PD-L1 immunohistochemistry (IHC) assays. METHODS: Tumor biopsy samples (N = 335) were assessed using four commercially available PD-L1 assays: VENTANA SP263, VENTANA SP142, PD-L1 IHC 28-8 pharmDx, and PD-L1 IHC 22C3 pharmDx. PD-L1 analytical staining and classification concordance, including agreement between clinically relevant scoring algorithms, were investigated using overall/positive/negative percentage agreement (OPA/PPA/NPA). RESULTS: Good analytical correlation was observed among the VENTANA SP263, PD-L1 IHC 22C3 pharmDx, and PD-L1 IHC 28-8 pharmDx assays for tumor cell (TC) and immune cell (IC) PD-L1 staining with Spearman rank coefficients of 0.92-0.93 for TCs and 0.88-0.91 for ICs. However, concordance (preset criterion: ≥85%) between patient PD-L1 status when applying the TC or ICICArea ≥ 25% (VENTANA SP263) cutoff was only achieved for PD-L1 IHC 22C3 pharmDx versus VENTANA SP263 (OPA 92.2%, PPA 86.4%, NPA 95.4%). Differences were observed between patient populations with UC tumors classified as PD-L1 high versus PD-L1 low/negative using combined positive score (CPS) ≥1, CPS ≥10, IC ≥5%, and TC/IC ≥25%. CONCLUSIONS: The VENTANA SP263 and PD-L1 IHC 22C3 pharmDx assays are analytically similar in UC. When the different PD-L1 assays were combined with their specified clinical scoring algorithms, differences were seen in patient classification driven by substantial differences in scoring approaches.

Agreement between Programmed Cell Death Ligand-1 Diagnostic Assays across Multiple Protein Expression Cutoffs in Non-Small Cell Lung Cancer.

Purpose: Immunotherapies targeting programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) demonstrate encouraging antitumor activity and manageable tolerability in non-small cell lung cancer (NSCLC), especially in patients with high tumor PD-L1 expression, as detected by companion or complementary diagnostic assays developed for individual agents. A laboratory is unlikely to use multiple assay platforms. Furthermore, commercially available diagnostic assays are not standardized, and different assay methods could lead to inappropriate treatment selection. This study establishes the extent of concordance between three validated, commercially available PD-L1 IHC diagnostic assays for NSCLC patients [Ventana SP263 (durvalumab), Dako 22C3 (pembrolizumab), and Dako 28-8 (nivolumab)].Experimental Design: Five hundred formalin-fixed, paraffin-embedded archival NSCLC samples were obtained from commercial sources. Stained slides were read in batches on an assay-by-assay basis by a single pathologist trained in all methods, in a Clinical Laboratory Improvements Amendments program-certified laboratory. An additional pathologist performed an independent review of 200 stained samples for each assay.Results: PD-L1 expression was evaluable with all assays in 493 samples. The three assays showed similar patterns of tumor membrane staining, with high correlation between percent PD-L1 staining. An overall percentage agreement of >90% was achieved between assays at multiple expression cutoffs, including 1%, 10%, 25%, and 50% tumor membrane staining.Conclusions: This study builds optimism that harmonization between assays may be possible, and that the three assays studied could potentially be used interchangeably to identify patients most likely to respond to anti-PD-1/PD-L1 immunotherapies, provided the appropriate clinically defined algorithm and agent are always linked. Clin Cancer Res; 23(14); 3585-91. ©2017 AACR.

Syncope from dynamic left ventricular outflow tract obstruction simulating hypertrophic cardiomyopathy in a patient with primary AL-type amyloid heart disease.

Dynamic left ventricular outflow tract (LVOT) obstruction is seen classically in hypertrophic cardiomyopathy. Cardiac amyloidosis can present with asymmetric hypertrophy that resembles hypertrophic cardiomyopathy, and, in some cases, with dynamic LVOT obstruction. The occurrence of syncope in such patients is not uncommon. The syncope is usually thought to be related to mechanisms other than LVOT obstruction, such as arrhythmias, conduction disturbances, orthostatic hypotension, or vasovagal effects associated with neuropathy.Herein, we report the case of a patient who had immunocyte-derived (primary AL-type) cardiac amyloidosis with the echocardiographic appearance of hypertrophic cardiomyopathy and evidence of LVOT obstruction that caused syncope. We were able to provoke and identify dynamic LVOT obstruction that produced presyncopal symptoms similar to those that typically occur in such patients spontaneously. Dynamic LVOT obstruction as a cause of syncope should be considered in patients who have cardiac amyloidosis and echocardiographic evidence of hypertrophic cardiomyopathy.

Osseous metaplasia in diffuse large B-cell lymphoma of the kidney.

A 57-year-old female with a history of diffuse large B-cell lymphoma (DLBCL) presented with a renal mass. Microscopic analysis of the nephrectomy specimen revealed DLBCL, confirmed by immunohistochemical analysis (CD45, CD20, CD3, pan-keratin) and polymerase chain reaction (PCR). Multiple spicules of metaplastic bone were identified within the tumor mass, but not within the uninvolved kidney parenchyma. No evidence of bone or dystrophic calcification was detected on the pre-nephrectomy computerized tomography (CT) scan. To our knowledge, this is the first incidence of osseous metaplasia occurring within DLBCL. The pathogenesis of osseous metaplasia is briefly discussed.

MRI findings of an intermuscular lipoma in a 2-year-old.

We report the MRI findings of a large deep intermuscular lipoma in a 2-year-old child with a painless palpable shoulder mass, and its differentiation from liposarcoma and other soft-tissue masses. To our knowledge, the imaging features of deep lipomas in children have not been reported.

The significance of the diagnosis of atypia in breast fine-needle aspiration.

The diagnosis of atypia in breast fine-needle aspiration (FNA) continues to be an area of debate in cytology practice. The aim of this study was to assess the clinical significance of this term and to evaluate potential morphological criteria, which would determine the patient's outcome. A computer-based search was carried out to retrieve breast FNAs performed between 1990 and 2000 that were diagnosed as atypical. Cases followed by surgical resection were reexamined for the presence of morphological features potentially differentiating benign and malignant lesions. Out of 1,568 breast FNAs, there were 64 cases (4%) with a diagnosis of atypia. Thirty-eight cases had surgical follow-up material that revealed malignancy in 14 cases (37%) and benign lesions in 24 cases (63%). The benign diagnostic categories included fibrocystic change (12/24), fibroadenoma (3/24), tubular adenoma (2/24), and nonspecific findings (7/24). The malignant diagnoses included ductal carcinoma (9/14), lobular carcinoma (3/14), ductal carcinoma in situ (DCIS; 1/14), and tubular carcinoma (1/14). The evaluation of cytological criteria used to differentiate benign from malignant lesions (i.e., cellularity, loss of cohesion, myoepithelial cells, nuclear enlargement, nuclear overlap, prominent nucleoli) revealed significant overlap between benign and malignant cases, particularly in cases of fibroadenoma, tubular adenoma, and proliferative breast disease. The surgical follow-up of four hypocellular cases revealed lobular carcinoma in two cases and ductal carcinoma in the remaining two cases. Our study confirmed that the diagnosis of atypia is clinically significant because it is associated with a high probability of malignancy. No morphological criterion is able to reliably differentiate benign and malignant lesions in cases diagnosed with atypia. Diagnosis of atypia is particularly significant in hypocellular cases. We recommended that breast FNAs with a diagnosis of atypia be evaluated further histologically.

Parafallopian tube transitional cell carcinoma.

BACKGROUND: Transitional cell carcinoma (TCC) has recently been acknowledged as a distinct histologic pattern of the uncommon primary fallopian tube carcinoma. However, rare cases of TCC that are closely associated to the extraluminal portion of the tube remain widely unrecognized. CASE: We present a left adnexal high-grade TCC in a 56-year-old postmenopausal woman with an elevated serum CA-125 level. The tumor was attached by a small stalk to the serosal surface of the left fallopian tube and was completely separate from the uninvolved uterus and ipsilateral ovary. Histologic examination of the tubal lumen epithelium revealed neither atypia nor involvement by the neoplasm. Immunohistochemistry showed the tumor cells to be positive for pankeratin, calretinin, progesterone and estrogen receptors, and cytokeratin 7, and negative for cytokeratin 20, consistent with a Mullerian derivation. CONCLUSION: Our case represents the fourth reported instance of a primary paratubal TCC. Perhaps, this entity falls under a previously unrecognized category of carcinomas that collectively may arise from Walthard's rest, paratubal cyst, or directly from the tubal serosa.