A Narrative Review-Management of Malignant Pleural Effusion Related to Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma (MPM) is an aggressive, almost universally fatal cancer with limited therapeutic options. Despite efforts, a real breakthrough in treatment and outcomes has been elusive. Pleural effusion with significant breathlessness and pain is the most typical presentation of individuals with MPM. Although thoracentesis provides relief of breathlessness, most such pleural effusions recur rapidly, and a definitive procedure is often required to prevent a recurrence. Unfortunately, the optimal treatment modality for individuals with recurrent MPM-related effusion is unclear, and considerable variation exists in practice. In addition, non-expandable lung is common in pleural effusions due to MPM and makes effective palliation of symptoms more difficult. This review delves into the latest advances in the available management options (both surgical and non-surgical) for dealing with pleural effusion and non-expandable lung related to MPM. We discuss factors that determine the choice of definitive procedures that need to be tailored to the individual patient.

Assessing Tumor-infiltrating Lymphocytes in Solid Tumors: A Practical Review for Pathologists and Proposal for a Standardized Method From the International Immunooncology Biomarkers Working Group: Part 1: Assessing the Host Immune Response, TILs in Invasive Breast Carcinoma and Ductal Carcinoma In Situ, Metastatic Tumor Deposits and Areas for Further Research.

Assessment of tumor-infiltrating lymphocytes (TILs) in histopathologic specimens can provide important prognostic information in diverse solid tumor types, and may also be of value in predicting response to treatments. However, implementation as a routine clinical biomarker has not yet been achieved. As successful use of immune checkpoint inhibitors and other forms of immunotherapy become a clinical reality, the need for widely applicable, accessible, and reliable immunooncology biomarkers is clear. In part 1 of this review we briefly discuss the host immune response to tumors and different approaches to TIL assessment. We propose a standardized methodology to assess TILs in solid tumors on hematoxylin and eosin sections, in both primary and metastatic settings, based on the International Immuno-Oncology Biomarker Working Group guidelines for TIL assessment in invasive breast carcinoma. A review of the literature regarding the value of TIL assessment in different solid tumor types follows in part 2. The method we propose is reproducible, affordable, easily applied, and has demonstrated prognostic and predictive significance in invasive breast carcinoma. This standardized methodology may be used as a reference against which other methods are compared, and should be evaluated for clinical validity and utility. Standardization of TIL assessment will help to improve consistency and reproducibility in this field, enrich both the quality and quantity of comparable evidence, and help to thoroughly evaluate the utility of TILs assessment in this era of immunotherapy.

Assessing Tumor-Infiltrating Lymphocytes in Solid Tumors: A Practical Review for Pathologists and Proposal for a Standardized Method from the International Immuno-Oncology Biomarkers Working Group: Part 2: TILs in Melanoma, Gastrointestinal Tract Carcinomas, Non-Small Cell Lung Carcinoma and Mesothelioma, Endometrial and Ovarian Carcinomas, Squamous Cell Carcinoma of the Head and Neck, Genitourinary Carcinomas, and Primary Brain Tumors.

Assessment of the immune response to tumors is growing in importance as the prognostic implications of this response are increasingly recognized, and as immunotherapies are evaluated and implemented in different tumor types. However, many different approaches can be used to assess and describe the immune response, which limits efforts at implementation as a routine clinical biomarker. In part 1 of this review, we have proposed a standardized methodology to assess tumor-infiltrating lymphocytes (TILs) in solid tumors, based on the International Immuno-Oncology Biomarkers Working Group guidelines for invasive breast carcinoma. In part 2 of this review, we discuss the available evidence for the prognostic and predictive value of TILs in common solid tumors, including carcinomas of the lung, gastrointestinal tract, genitourinary system, gynecologic system, and head and neck, as well as primary brain tumors, mesothelioma and melanoma. The particularities and different emphases in TIL assessment in different tumor types are discussed. The standardized methodology we propose can be adapted to different tumor types and may be used as a standard against which other approaches can be compared. Standardization of TIL assessment will help clinicians, researchers and pathologists to conclusively evaluate the utility of this simple biomarker in the current era of immunotherapy.

Digital PCR of Genomic Rearrangements for Monitoring Circulating Tumour DNA.

Identifying circulating tumour DNA (ctDNA) for monitoring of cancer therapy is dependent on the development of readily designed, sensitive cancer-specific DNA markers. Genomic rearrangements that are present in the vast majority of cancers provide such markers.Tumour DNA isolated from two fresh-frozen lung tumours underwent whole genome sequencing. Genomic rearrangements were detected using a new computational algorithm, GRIDSS. Four genomic rearrangements from each tumour were chosen for further study using rearrangement-specific primers. Six of the eight rearrangements tested were identified as tumour-specific, the remaining two were present in the germline. ctDNA was quantified using digital PCR for the tumour genomic rearrangements in patient blood. Interestingly, one of the patients had no detectable ctDNA either prior to or post surgery although the rearrangements were readily detectable in the tumour DNA.This study demonstrates the feasibility of using digital PCR based on genomic rearrangements for the monitoring of minimal residual disease. In addition, whole genome sequencing provided further information enabling therapeutic choices including the identification of a cryptic EGFR exon 19 deletion in one patient and the identification of a high somatic mutation load in the other patient. This approach can be used as a model for all cancers with rearranged genomes.

Large spontaneous lung hernia-a case report.

Intercostal lung hernias can be results of trauma or surgery. True spontaneous lung hernias thought to be a result of sudden acute increase in intrathoracic pressures are extremely rare. Only 51 cases have been reported in literature over the past four-and-half decades. We report a case of spontaneous chest wall posterior-lateral lung herniation that developed in a 73-year-old following severe coughing and straining during an episode of lower respiratory tract infection. Herein we present the unusual findings in the case and outline the pathophysiology of the problem and management options available.

Minimally Invasive Thoracic Surgery for Low- and Middle-Income Countries.

The burden of respiratory and upper-gastrointestinal diseases especially affects low- and middle-income countries. Five billion people lack access to safe, timely, and affordable surgical care, including thoracic surgical care. Minimally invasive thoracic surgery (MITS) has been shown to reduce complications, shorten hospital lengths of stay, and minimize health care costs, thereby enabling patients to pay less out-of-pocket and/or limit time away from work and families. Experiences with MITS exist but are limited in low- and middle-income countries; professional societies, academic institutions, policymakers, and industry can facilitate scale-up of MITS by increasing financing, expanding surgical training, and optimizing surgical supply chains.

An Audit of the Outcomes of Thymic Surgery.

Most pathology of the thymus gland warrant its surgical removal; and this requires significant expertise and adequate medical set-up. This study aimed to audit the results of thymectomies performed in a specialised tertiary level centre in a resource-poor country. The outcomes of open and minimally invasive video-assisted thoracoscopic surgery (VATS) thymectomies were also compared. Out of 58 patients operated at Department of Thoracic Surgery, Manmohan Cardiothoracic Vascular and Transplant Center, Maharajgunj, Kathmandu, Nepal between October 2012 and January 2019, 33 patients underwent open thymectomy and 25 had VATS thymectomy. We conducted a retrospective search to look at operative time, blood loss and length of postoperative hospitalisation. The open surgery group was followed for an average of 32 months, and the VATS cohort for 38 months. No significant differences were found in mean operative times and overall survival between groups. In selected cases, thymectomy via VATS is safer and comparable to open thymectomy in terms of operative safety and oncological completeness. Key Words: Thymus, VATS, Thymectomy, Outcome.

Expression of EGFR and conformational forms of EGFR in malignant pleural mesothelioma and its impact on survival.

AIM: Conformational forms of the epidermal growth factor receptor (EGFR) are pro-tumorigenic. The prevalence and impact of conformational forms of EGFR in malignant mesothelioma (MM) is unknown. We investigated expression of EGFR and conformational forms of EGFR by immunohistochemistry using EGFR-targeting monoclonal antibodies (mAb). In addition, EGFR gene amplification was investigated by fluorescent in-situ hybridization (FISH). Findings were correlated with survival. METHODS: Patients treated between 1988 and 2014 were identified from the thoracic surgery database of the Austin Hospital, Melbourne, Australia. Tissue microarrays (TMAs) were constructed, subjected to wild type (wt) EGFR IHC staining and FISH analysis. Conformational and mutation forms of EGFR were detected by IHC using mAb806, and LMH-151 which detects EGFRVIII. `H-scores` were derived and EGFR expression correlated with survival by Kaplan-Meier and log rank analysis. RESULTS: WtEGFR expression was seen in 93 % (299/321) of cases with overexpression (defined as an H-score ≥200) seen in more than half of cases (64 %). EGFR overexpression in MM was seen more commonly in the epithelioid subtype. EGFR overexpression was not associated with true EGFR amplification, although multiple copies were appreciated in samples with polysomy. EGFR expression did not correlate with survival. A conformational form of EGFR associated with EGFR dysregulation was found in 8.2 % of cases, and patients with these tumors had a trend towards a poorer outcome. No cases of the EGFRVIII mutation were identified. CONCLUSION: MM consistently demonstrated high expression of EGFR, with a subset of tumors showing conformational EGFR forms consistent with EGFR dysregulation, but withoutEGFR amplification or EGFR VIII mutation. wtEGFR expression did not influence survival. The impact of EGFR conformation on survival warrants further investigation.

Analysis of angiogenic and stromal biomarkers in a large malignant mesothelioma cohort.

BACKGROUND: Malignant mesothelioma (MM) is an aggressive malignancy of the pleura and other mesothelial membranes. Agents targeting vascular endothelial growth factor (VEGF) such as bevacizumab; and multi-kinase inhibitors such as nintedanib [angiokinase inhibitor of VEGF, platelet-derived growth factor (PDGF) receptor and fibroblast growth factor receptor (FGFR)] have recently demonstrated efficacy in MM. METHODS: Tissue microarrays (TMAs) were created from formalin-fixed, paraffin-embedded tissue samples obtained from 326 patients with MM who were treated surgically. PDGF-CC, FGFR-1, VEGF and CD31 expression were analysed by immunohistochemical (IHC) staining. The H-score method assigned a score of 0-300 to each sample, based on the percentage of cells stained at different intensities. CD31 was evaluated via Chalkley's method to evaluate microvessel density. We evaluated the association between expression of the biomarkers, clinicopathological factors and outcomes, in patients with MM. RESULTS: CD31 high (≥5) was seen in only 31/302 (10.3%) irrespective of histology. PDGF-CC high (≥150) was seen in 203 /310 (65%) of all samples. VEGF high (≥80) was seen in 219/322 (68%) of all MM with 143/209 (68%) of epithelioid histology. FGFR-1 high (≥40) was seen in 127/310 (41%) of all MM. There was no association of VEGF and FGFR-1 IHC with survival nor differences between histological subtypes. There was a non-significant trend towards poorer survival in epithelioid tumours with increased PDGF-CC expression (OS 18.5 vs 13.2 months; HR 0.7928; 95% CI 0.5958 to 1.055, P = 0.1110). High CD31 score was associated with significantly poorer survival (OS 12 vs 8.6 months; HR 0.48; 95% CI 0.2873 to 0.7941, P = 0.0044). Of the 31 patients with high CD31 scores; 23/31 (74%) were also high for PDGF-CC and 20/31 (64%) with high VEGF scores. CD31 was found to be an independent prognostic factor in multivariate analysis (HR 1.540; 95% CI 1.018 to 2.330; p = 0.041). CONCLUSIONS: High CD31 was an independent poor prognostic factor and high PDGF-CC expression was associated with poor survival in MM. Abrogating these pathways may have prognostic implications.

NTRK and ALK rearrangements in malignant pleural mesothelioma, pulmonary neuroendocrine tumours and non-small cell lung cancer.

OBJECTIVES: Gene rearrangements involving NTRK1, NTRK2, NTRK3, ROS1 and ALK have been identified in many types of cancer, including non-small cell lung cancer (NSCLC). Data in malignant pleural mesothelioma (MPM), lung neuroendocrine tumors (NETs) and small-cell lung cancer (SCLC) are lacking. Given the activity of NTRK, ROS-1 and ALK inhibitors in tumors harboring gene fusions, we sought to explore such rearrangements in these less common tumors in addition to NSCLC. METHODS: Archival tumor tissue from patients with MPM, lung NETs, SCLC and NSCLC were used to create tissue microarrays. Immunohistochemistry (IHC) was performed using a cocktail of antibodies against TRK, ROS1 and ALK. IHC positive samples underwent RNA sequencing using the ArcherDX FusionPlex CTL diagnostic assay. Clinical data were obtained through retrospective chart review. RESULTS: We performed IHC on 1116 samples: 335 MPMs, 522 NSCLCs, 105 SCLCs and 154 lung NETs. There were 23 IHC positive cases (2.1%) including eight MPMs (2.4%), eight NETs (5.2%), five SCLC (4.8%) and two NSCLC (0.4%). The following fusions were detected: one MPM with an NTRK ex10-TPM3 ex8, another MPM with an ALK ex20-EML4ex13, one lung intermediate-grade NET (atypical carcinoid) with an ALK ex20-EML4 ex6/intron6, and two NSCLCs with an ALK ex20-EML4 ex6/intron6 rearrangement. None of the patients received targeted treatment. CONCLUSIONS: To our knowledge, we report for the first time NTRK and ALK rearrangements in a small subset of MPM. An ALK rearrangement was also detected in lung intermediate-grade NET (or atypical carcinoid). Our data suggest that IHC could be a useful screening test in such patients to ensure that all therapeutic strategies including targeted therapy are utilized.

BCL-XL is an actionable target for treatment of malignant pleural mesothelioma.

Despite having one of the lowest survival rates of all cancers, there have been no new approved treatments for malignant pleural mesothelioma (MPM) in over a decade. Standard-of-care treatment relies on Cisplatin plus Pemetrexed chemotherapy. Here, we tested a suite of BH3-mimetic drugs targeting BCL-2 pro-survival proteins of the intrinsic apoptotic pathway. We found BCL-XL is the dominant pro-survival protein in a panel of cell lines in vitro, though potent, synergistic cell killing occurred with MCL-1 co-targeting. This correlates with high-level expression of BCL-XL and MCL-1 in cell lines and a large cohort of patient tumour samples. BCL-XL inhibition combined with Cisplatin also enhanced cell killing. In vivo BCL-XL inhibition was as effective as Cisplatin, and the combination enhanced tumour growth control and survival. Genetic ablation of MCL-1 also enhanced the effects of BCL-XL inhibitors, in vivo. Combined, these data provide a compelling rationale for the clinical investigation of BH3-mimetics targeting BCL-XL in MPM.

Bronchial injuries: a tale of differing presentations.

Bronchial disruptions are uncommon but nevertheless grievous injuries and are usually secondary to major thoracic trauma. Although many are associated with other catastrophic injuries causing early mortality, their presentations can be late and they are often difficult to diagnose. Their management is frequently challenging and the ideal course of treatment is not yet clearly defined. Here, we describe two cases of main bronchial injuries presenting to us with post-traumatic collapse lung, albeit with a widely differing post-trauma course. Both required thoracotomy followed by a resection and anastomosis of the disrupted/stenotic segment. Operative results were good with both cases showing a well-expanded lung and no postoperative anastomotic site stenosis during the period of follow-up. Our experience highlights that patients with major bronchial injuries can have varying presentations. High degree of suspicion is necessary for early diagnosis and prompt surgical treatment. Resection of the stenosed/fibrosed segment followed by anastomosis yields good results.

Esophageal 'pyocele': thoracoscopic management.

Mucocele of the native esophagus is a rare complication after esophageal bypass surgery for various indications. Esophageal mucoceles rarely get infected, forming a 'pyocele' which becomes symptomatic. Various approaches have been utilized in the management of such pyoceles. We report a similar patient managed successfully in our center utilizing a thoracoscopic deroofing and partial excision of the pyocele.

Surgery for parasitic lung infestations: roles in diagnosis and treatment.

Pulmonary parasitic infestations are a worldwide problem associated with significant morbidity and socioeconomic impact. They are known to have varied clinical presentations and radiological appearances. Prevention of parasite transmission and medical treatment of cases form the two pillars of control of these diseases. The role of surgery is limited to the diagnosis and definitive treatment of the minority of pulmonary parasitic afflictions, most notably hydatidosis. Despite surgery being established as the treatment of choice in pulmonary hydatid cysts (PHCs) for over half a century, variations and unresolved controversies persist regarding the best surgical technique. Complications brought on by cyst rupture, multiplicity and multi-organ involvement add complexity to treatment decisions. The development of video-assisted thoracoscopic surgery (VATS) brings the promise of reduced peri-operative morbidity but is yet to be universally accepted as a safe technique. In this review, we endeavor to discuss the common pulmonary infestations focusing on the current trends and controversies surrounding surgery for PHC.

Mismatch Repair Protein Defects and Microsatellite Instability in Malignant Pleural Mesothelioma.

INTRODUCTION: Malignant pleural mesothelioma is an aggressive malignancy with limited systemic therapy options. Promising results have been reported with use of anti-programmed cell death 1 therapy; however, its benefits appear to be confined to a subgroup of patients. Microsatellite instability (MSI) results from the inactivation of DNA mismatch repair genes and results in a high tumor mutational burden, a phenomenon that has not been seen with mesothelioma. MSI and protein absence have been shown to correlate in colorectal cancer, such that most centers have adopted immunohistochemistry (IHC) to screen for MSI-high colorectal cancers. We profiled a large cohort of patients with mesothelioma to determine the rate of negative IHC staining results the four common mismatch repair proteins. DESIGN: A tissue microarray comprising 335 patients with malignant pleural mesothelioma were used. IHC for the four common mismatch repair proteins (mutL homolog 1; PMS1 homolog 2, mismatch repair system component; mutS homolog 2; and mutS homolog 6) was performed. Programmed death ligand 1 IHC staining with the E1L3N clone was also performed. DNA was isolated from IHC equivocal samples and analyzed for microsatellite instability by using the Promega MSI Analysis System (version 1.2, Promega, Madison, WI). RESULTS: Of the patients profiled, 329 had intact mismatch repair proteins by IHC. Six samples with IHC testing results indicating absent mismatch repair protein were analyzed for MSI and confirmed to be negative. Of the six IHC-negative samples, five were negative for programmed death ligand 1 staining and one sample had more than 5% staining. CONCLUSION: In this large retrospective series, we were unable to identify any patients with malignant pleural mesothelioma with microsatellite instability. Response to anti-programmed cell death 1-based immunotherapy may be driven by other mechanisms.

Pembrolizumab as Palliative Immunotherapy in Malignant Pleural Mesothelioma.

INTRODUCTION: There is no approved second-line treatment for malignant pleural mesothelioma (MPM). On the basis of promising early results, pembrolizumab was used off-label in Switzerland and Australia. We investigated outcomes in association with clinicopathological features and expression of programmed death ligand 1 (PD-L1). METHODS: Registry data in Australia and Switzerland were pooled. Patient characteristics, including age, sex, histological subtype, and previous treatments were captured. Outcomes were assessed locally. PD-L1 expression was categorized as negative (<5%), intermediate (5%-49%), and high (≥50%). RESULTS: A total of 93 patients (48 from Switzerland and 45 from Australia) were treated; 68 patients (73%) had epithelioid MPM, and 67 (72%) had an Eastern Cooperative Oncology Group performance status of 0 or 1. Pembrolizumab was the second-line treatment in 48 of 93 patients (52%). PD-L1 expression results were available for 66 patients (71%). Most (68%) were negative, 18% were intermediate, and 14% were high for PD-L1 expression. In the full cohort, the overall response rate (ORR) was 18%, the median progression-free survival (mPFS) was 3.1 months, and the median overall survival was 7.2 months. In patients with an Eastern Cooperative Oncology Group performance status of 0 or 1 and only one previous systemic treatment (n = 35), the ORR was 37%, the mPFS was 3.7 months, and the median overall survival was 10.2 months. The nonepitheloid histological subtype showed an improved ORR (24% versus 16% [p = 0.54) and mPFS (5.6 versus 2.8 months [p = 0.02]). Compared with intermediate and negative PD-L1 expression, high PD-L1 expression was associated with an improved ORR (44% versus 42% versus 11% [p = 0.01]) and mPFS (6.2 versus 3.9 versus 2.7 months [p = 0.04]). Toxicity was as expected. CONCLUSION: These real-world data demonstrate similar response rates but inferior survival compared with those in early-phase trials. High PD-L1 expression and nonepitheloid histological subtype were associated with greater activity. Anti-PD-L1 immunotherapy is a reasonable second-line therapy in patients with MPM.

The Immune Microenvironment, Genome-wide Copy Number Aberrations, and Survival in Mesothelioma.

INTRODUCTION: Results of recent clinical studies of immune checkpoint inhibitors in malignant pleural mesothelioma (MPM) have dampened initial enthusiasm. However, the immune environment and targets of these treatments such as programmed cell death protein 1 and its ligand programmed death ligand 1 (PD-L1) have not been well characterized in MPM. Using a large cohort of patients, we investigated PD-L1 expression, immune infiltrates, and genome-wide copy number status and correlated them to clinicopathological features. METHODS: Tissue microarrays were constructed and stained with PD-L1(clone E1L3N [Cell Signaling Technology, Danvers, MA]), cluster of differentiation 4, cluster of differentiation 8, and forkhead box P3 antibodies. PD-L1 positivity was defined as at least 5% membranous staining regardless of intensity, and high PD-L1 positivity was defined as at least 50%. Genomic DNA from a representative subset of 113 patients was used for genome-wide copy number analysis. The percent genome alteration was computed as a proxy for genomic instability, and statistical analyses were used to relate copy number aberrations to other variables. RESULTS: Among 329 patients evaluated, PD-L1 positivity was detected in 130 of 311 (41.7%), but high PD-L1 positivity was seen in only 30 of 311 (9.6%). PD-L1 positivity correlated with nonepithelioid histological subtype and increased infiltration with cluster of differentiation 4-positive, cluster of differentiation 8-positive, and forkhead box P3-positive lymphocytes. High PD-L1-positive expression correlated with worse prognosis (hazard ratio = 2.37, 95% confidence interval: 1.57-3.56, p < 0.001) in univariate analysis but not in multivariate analysis. Higher percent genome alteration was associated with epithelioid histological subtype and poorer survival (hazard ratio = 1.59, 95% confidence interval: 1.01-2.5, p = 0.04) but not PD-L1 expression. CONCLUSIONS: PD-L1 expression was associated with nonepithelioid MPM, poor clinical outcome, and increased immunological infiltrates. Increased genomic instability did not correlate with PD-L1 expression but was associated with poorer survival.

Immunotherapy for malignant mesothelioma: reality check.

INTRODUCTION: Initial data of immune based therapy showed promise for improving malignant mesothelioma (MM) treatment. However, the results of such treatments have neither been predictable nor consistent and recent clinical studies of immune checkpoint inhibitors in MM have dampened initial enthusiasm. Areas covered: We comprehensively discuss the basis, modalities and updated results of immunotherapy in MM. An online search was conducted for relevant literature and abstracts of recent meetings. Expert commentary: Although initial studies have demonstrated proof of principle that manipulating the immune checkpoint axis holds promise in MM, results of some recent large studies using checkpoint inhibitors have been disappointing. This is not surprising given the low mutational load in MM and suggests that single agent immunotherapy has limited benefit in this disease. We believe that in order to demonstrate durable survival benefits, they will need to be used in combination approaches with other immunotherapies, vaccines or chemotherapy.

Calretinin but not caveolin-1 correlates with tumour histology and survival in malignant mesothelioma.

Malignant mesothelioma (MM) continues to be a disease with poor prognosis and limited treatment options. Calretinin and caveolin-1 expression by tumour in MM have recently been described to be associated with tumour histology, differentiation and consequently survival. In a large, well annotated cohort, we studied both of these biomarkers and explored their association with clinicopathological parameters and survival. A retrospective search of patients with MM who underwent surgery at the Austin Hospital in Melbourne, Australia, was conducted. Clinical history and outcome data were retrieved from patient records. Tissue microarrays (TMAs) were constructed and stained for calretinin and caveolin-1. 'H scores' were derived, taking intensity and distribution of staining, and the cohort was dichotomised using median values for both markers. In the 329 patients evaluated, median age was 67 years. Males outnumbered females by 5:1. Epithelioid histology 202/319 (62.9%) was the most common, followed by biphasic 72/319 (21.8%) and sarcomatoid 45/319 (13.6%); histology could not be confirmed in 10 patients. Calretinin expression was detected in 246 of the 324 (76%) evaluable patients and high expression was associated with epithelioid histology (p < 0.0001). Caveolin-1 was expressed in 298 (94%) of 317 evaluable patients which was much higher compared to its expression in a cohort of lung adenocarcinomas (8/58, 13.7%). However, no association with histology was found (p = 0.409). When taken as a continuous variable, calretinin expression was found to be an independent predictor of survival, alongside histology, neutrophil-lymphocyte ratio, weight loss and stage. No prognostic value was demonstrable for caveolin-1 expression and calretinin/caveolin-1 ratio. There was no relationship between calretinin and caveolin-1 expression. In MM, increased calretinin expression is associated with epithelioid histology and better survival. Caveolin-1 is a sensitive MM marker and is expressed in a high proportion of cases but lacks association with histology and survival.