BACKGROUNDMalignant transformation of cells is frequently associated with abnormalities in human leukocyte antigen (HLA) expression. These abnormalities may play a role in the clinical course of the disease, because HLAs mediate interactions of tumor cells with cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. Retinoblastoma is the most common intraocular malignant tumor in childhood and is characterized by direct spread to the optic nerve and orbit as well as hematogeneous and lymphatic spread. Little is known about the role of HLA expression in the progression of this malignant disease.METHODSHLA Class I antigen, β2‐microglobulin (β2‐m), HLA Class II antigens, and the antigen‐processing molecules (APMs) of the HLA Class I pathway, including proteasomal subunits (low–molecular mass polypeptide 2 [LMP‐2] and LMP‐10), the transporter‐associated protein (TAP‐1) subunit, the binding protein tapasin, and the chaperone molecule calnexin, were studied in 30 archival retinoblastoma specimens by immunohistochemistry. Immunoanalysis was performed based on the International Histocompatibility Working Group Project Description.RESULTSHLA Class I antigen, β2‐m, HLA Class II antigen, and APMs were positive in 12 tumors with no invasion and were decreased in 13 tumors with choroidal and optic nerve invasion. The difference in HLA and APM expression between the 2 groups was statistically significant (P < 0.001).CONCLUSIONSDecreased expression of HLA was observed in aggressive tumors and in poorly differentiated tumors. The current findings support a role for both CTLs and NK cell‐mediated control of tumor growth in the clinical course of retinoblastoma. Cancer 2004;100:1059–69. © 2004 American Cancer Society.

Avascular necrosis (AVN) of head of the femur is associated with various pathological conditions and treatment modalities. We present a case of acute promyelocytic leukemia who was treated with all-transretinoic acid (ATRA), daunomycin, cytarabine and a short course of dexamethasone. He developed AVN of bone after 2 years of treatment. Whether this is related to ATRA is dealt with in the discussion.

Literature data on the clinical pharmacokinetics of various VEGFR-2 inhibitors along with in vitro potency data were correlated and a linear relationship was established in spite of limited data set. In this work, a model set comprised of axitinib, recentin, sunitinib, pazopanib, and sorafenib were used. The in vitro potencies of the model set compounds were correlated with the published unbound plasma concentrations (Cmax, Cavg, Ctrough). The established linear regression (r2>0.90) equation was used to predict Cmax, Cavg, Ctrough of the 'prediction set' (motesanib, telatinib, CP547632, vatalanib, vandetanib) using in vitro potency and unbound protein free fraction. Cavg and Ctrough of prediction set were closely matched (0.2-1.8 fold of reported), demonstrating the usefulness of such predictions for tracking the target related modulation and/or efficacy signals within the clinically optimized population average. In case of Cmax where correlation was least anticipated, the predicted values were within 0.1-1.1 fold of those reported. Such predictions of appropriate parameters would provide rough estimates of whether or not therapeutically relevant dose(s) have been administered when clinical investigations of novel agents of this class are being performed. Therefore, it may aid in increasing clinical doses to a desired level if safety of the compound does not compromise such dose increases. In conclusion, the proposed model may prospectively guide the dosing strategies and would greatly aid the development of novel compounds in this class.

HLA class I antigen and beta 2 microglobulin are negative in melanomas with no extrascleral extension and liver metastases and weak in melanomas with extrascleral extension and are positive in melanomas with liver metastases. HLA expression is independent of the conventional markers in uveal melanoma.

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Cyclizine 50 mg is bioequivalent to the reference.

Human leukocyte class II antigen immunoexpression is decreased in conjunctival precancerous and squamous cell carcinomas.

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