Lung cancer-induced blindness

Cancer-Induced, Immune-Mediated Ocular Degenerations

The means whereby vision can be lost from a disease located distant from the eye include autoimmunity, with sensitization resulting from extraocular stimuli, a process illustrated here by the immunologic confusion caused by cancers. The uncontrolled proliferation of malignancies commonly involves the expression of components of the central nervous system, but a damaging loss of tolerance is rare. When autoimmunity does develop, organ-specific antigens are more often involved than the more generalized and widely disseminated common neuronal components. A focus upon a single antigen is typical of the immune-mediated paraneoplasia, a collection of syndromes identified by unusual antibody reactions. This review provides an outline of the immunologic trail that led to the recognition of autoimmunity in paraneoplastic ocular degenerations, how specific antibody reactions aid in diagnosis, and the possibility of including antibodies in modes for sight-saving intervention. 'Those who do not know history are destined to repeat it'.

Establishment of a novel small cell lung carcinoma cell line with specific recoverin expression from a patient with cancer-associated retinopathy

We analysed the biologic properties of a small cell lung carcinoma cell line (designated KK0206) established from a patient with SCLC who had cancer-associated retinopathy (CAR). Morphological and immunohistochemical studies showed that KK0206 cells have features of the classic type of SCLC. KK0206 cells grew in suspension, forming relatively small clumps of cells with a doubling time of 72 h. On light microscopy, the cells were relatively small with little cytoplasm. On immunohistochemistry using anti-bovine recoverin rabbit antibody, the cells were intensely positive for recoverin. In addition, they were positive for NSE, Ki-67, and TP53. They also expressed human recoverin, a photoreceptor protein, whose presence was confirmed by RT-PCR analysis with cDNA sequencing and Western blot analysis. The point mutation of their TP53 gene (exon 156) was detected as well. The present study demonstrates that human recoverin is expressed in SCLC cells cultured from an anti-recoverin antibody-negative patient with CAR. KK0206 might be important for further research on SCLC related retinopathy.

Incidence of antiretinal antibodies in melanoma: screening of 77 serum samples from 51 patients with American Joint Committee on Cancer stage I-IV

BACKGROUND

Patients with melanoma-associated retinopathy (MAR) experience different visual symptoms caused by the production of antitumoral antibodies that cross-react with retinal epitopes. Immunofluorescence assays of serum from patients with MAR on sectioned monkey or human retina characteristically reveal antibody activity located within the inner nuclear layer, with a focus of activity upon the membranes of bipolar cells.

OBJECTIVES

We inquired into the association with disease of this serological abnormality by evaluating sera from patients with melanoma with no MAR-like signs or symptoms.

METHODS

Groups of patients were selected with different stages of melanoma (American Joint Committee on Cancer stages I-IV). Seventy-seven serum samples from 51 patients with melanoma were examined by indirect immunohistochemical assay on sections of human retina.

RESULTS

Of the 77 serum samples, 53 were found to contain antibodies reactive with various components of retina. Eight were from 17 sera from patients in stage I or II, 14 were from 23 sera from patients in stage III, and 31 were from 37 sera from patients in stage IV. Statistical analysis revealed a correlation between antibody activity and the stage of disease, with a higher percentage of antibody activity in advanced stages (P = 0.002).

CONCLUSIONS

The presence of antiretinal antibodies in patients with melanoma without ocular symptoms appears to be more common than previously suspected. Antibody activity similar to that ascribed to the MAR syndrome appears in some patients with melanoma who have no MAR-like retinopathy. Follow-up studies will determine if patients with antiretinal antibodies go on to develop MAR and if staining intensity and staining patterns change over the course of the disease.

Recoverin as a paraneoplastic antigen in lung cancer: the occurrence of anti-recoverin autoantibodies in sera and recoverin in tumors

Using immunoblotting with recombinant recoverin as an antigen, we have examined 279 serum samples from individuals with small cell lung carcinoma (SCLC, 99 patients), non-small cell lung carcinoma (NSCLC, 44 patients), and non-malignant pulmonary disorders (86 patients) as well as sera from 50 healthy donors. Autoantibodies against recoverin (anti-Rc) were detected in sera from 15 patients with SCLC (15% of cases) and from 9 patients with NSCLC (about 20% of cases). Only two anti-Rc positive cases were detected in patients with non-malignant pulmonary disorders, while no such cases were found in healthy individuals. Immunohistochemical investigation of paraffin sections of 44 SCLC and 40 NSCLC tumors revealed recoverin-positive reaction in 30 SCLC (68%) and 34 NSCLC (85%) sections. Despite the high specificity (98%), the low sensitivity (less than 20%) does not allow serum anti-Rc to be considered as a valuable marker of lung cancer. However, taking into account the high occurrence of aberrant expression of recoverin in lung tumors, this PNA could be considered as a potential target for immunotherapy of lung cancer.

Autoantibodies to photoreceptor membrane proteins and outer plexiform layer in patients with cancer-associated retinopathy

Cancer-associated retinopathy (CAR) is a paraneoplastic syndrome that is characterized by degeneration of the retina as a remote effect of cancer outside the eye. The detection of autoantibodies associated with the retinopathy may precede the diagnosis of the underlying cancer. We have examined the sera of two patients with CAR by Western blot analysis. Autoantibodies to a 40kD antigen doublet and a 35 kD antigen were detected. Tissue specificity of the autoantigens was determined by testing several different tissues. The 40 kD antigen doublet was most abundant in retinal extract but was also present in lung and spleen extracts. The 35 kD antigen showed little tissue specificity and was present in all tissues tested. Fractionation of retinal proteins into water-soluble and -insoluble proteins revealed that the 40 kD antigen doublet was highly insoluble and probably represented membrane-associated proteins. Immunohistochemical analysis of the retina showed that the 40 kD antigens locate to the photoreceptors while the 35 kD antigen is located in the outer plexiform layer.

Neoplastic masquerade syndromes

Masquerade syndromes are classically defined as entities which emulate inflammatory conditions but which are in fact due to a neoplastic process. Careful history and examination in concert with appropriate ancillary investigations and histopathologic evaluation of tissue specimens are required in order to make the correct diagnosis. Many conditions may result in an appearance mimicking an inflammatory condition. The authors review neoplastic conditions which may be considered masquerades. The most common of these is primary intraocular lymphoma or primary central nervous system lymphoma, occurring predominately in older individuals. Diagnostic strategies, therapy, and prognosis are reviewed in detail. Other conditions that can be considered masquerade syndromes are reviewed as well, including lymphomatous and nonlymphomatous conditions, such as melanoma, retinoblastoma, juvenile xanthogranuloma, metastatic lesions, and paraneoplastic syndromes, among others.

[Mechanisms of paraneoplastic neurologic syndromes]

INTRODUCTION

Paraneoplastic neurological syndromes (PNS) refer to a set of neurological disorders associated with neuronal degeneration in some patients with systemic cancers. These disorders are not related to the tumor mass or metastasis.

CURRENT KNOWLEDGE AND KEY POINTS

Evidence argues for an autoimmune reaction against tumor cells which expresses antigens normally present in neurons. A high percentage of patients with PNS harbors high titers of anti-neuronal autoantibodies in their serum and cerebrospinal fluid. In addition to their clinical interest in diagnosis and pathophysiology, these autoantibodies provide a unique opportunity to identify genes encoding previously undiscovered neuronal proteins which are also expressed by tumor cells. These "onconeural" antigens have been classified in four groups: neuromuscular junction proteins, nerve terminal/vesicle-associated proteins, neuronal RNA binding proteins, or neuronal signal transduction proteins.

FUTURE PROSPECTS AND PROJECTS

All of these proteins would play a major role in the neuronal maturation and homeostasis, and for some of them in cellular proliferation. Better understanding of the exact role of these proteins would in turn permit better understanding of the mechanisms of neuronal degeneration and tumor cell proliferation in PNS.