Combined treatment with radiotherapy, chemotherapy and avelumab results in regression of metastatic Merkel cell carcinoma and improvement of associated Lambert-Eaton myasthenic syndrome: A case report.

Merkel cell carcinoma (MCC) is a rare and highly aggressive neuroendocrine malignancy arising from mechanoreceptors in the basal epidermis. Due to a pronounced risk of spread and a high propensity for recurrence after treatment, immediate treatment is of utmost importance. Lambert-Eaton myasthenic syndrome (LEMS) is a paraneoplastic phenomenon affecting the muscles with autoimmune pathophysiology, and >50% of known cases are associated with an underlying malignancy. In the present report, the case of a 67-year-old man presenting with progressive proximal muscle weakness, autonomic dysfunction and involuntary weight loss is described. Symptoms and detection of voltage-gated calcium channel antibodies were consistent with LEMS. Distant metastases were found in the inguinal and iliac lymph nodes, and these were immunohistochemically confirmed to be of epithelial and neuroendocrine origin, consistent with MCC. Local radiotherapy and chemotherapy improved the symptoms; however, a change of treatment was required due to the side effects of the chemotherapy. Avelumab, an immune checkpoint inhibitor, was therefore introduced, and within a year the patient did not only experience tumor remission but also exhibited marked improvements in muscle strength and mobility. At present, 2 years later, the MCC is still in remission. To the best of our knowledge, the present report is the first to describe MCC with associated LEMS, which was successfully treated with avelumab after previous radiotherapy and chemotherapy, with both improved functional motor recovery and tumor reduction. In conclusion, the present case report demonstrated that the present treatment strategy is a potential treatment option and could thus be considered in similar cases.

Plasma and bronchoalveolar lavage fluid oxylipin levels in experimental porcine lung injury.

Inflammatory signaling pathways involving eicosanoids and other regulatory lipid mediators are a subject of intensive study, and a role for these in acute lung injury is not yet well understood. We hypothesized that oxylipin release from lung injury could be detected in bronchoalveolar lavage fluid and in plasma. In a porcine model of surfactant depletion, ventilation with hyperinflation was assessed. Bronchoalveolar lavage and plasma samples were analyzed for 37 different fatty acid metabolites (oxylipins). Over time, hyperinflation altered concentrations of 4 oxylipins in plasma (TXB2, PGE2, 15-HETE and 11-HETE), and 9 oxylipins in bronchoalveolar lavage fluid (PGF2α, PGE2, PGD2, 12,13-DiHOME, 11,12-DiHETrE, 13-HODE, 9-HODE, 15-HETE, 11-HETE). Acute lung injury caused by high tidal volume ventilation in this porcine model was associated with rapid changes in some elements of the oxylipin profile, detectable in lavage fluid, and plasma. These oxylipins may be relevant in the pathogenesis of acute lung injury by hyperinflation.

PD-L1 immunohistochemistry in clinical diagnostics of lung cancer: inter-pathologist variability is higher than assay variability.

Assessment of programmed cell death ligand 1 (PD-L1) immunohistochemical staining is used for decision on treatment with programmed cell death 1 and PD-L1 checkpoint inhibitors in lung adenocarcinomas and squamous cell carcinomas. This study aimed to compare the staining properties of tumor cells between the antibody clones 28-8, 22C3, SP142, and SP263 and investigate interrater variation between pathologists to see if these stainings can be safely evaluated in the clinical setting. Using consecutive sections from a tissue microarray with tumor tissue from 55 resected lung cancer cases, staining with five PD-L1 assays (28-8 from two different vendors, 22C3, SP142, and SP263) was performed. Seven pathologists individually evaluated the percentage of positive tumor cells, scoring each sample applying cutoff levels used in clinical studies: <1% positive tumor cells (score 0), 1-4% (score 1), 5-9% (score 2), 10-24% (score 3), 25-49% (score 4), and >50% positive tumor cells (score 5). Pairwise analysis of antibody clones showed weighted kappa values in the range of 0.45-0.91 with the highest values for comparisons with 22C3 and 28-8 and the lowest involving SP142. Excluding SP142 resulted in kappa 0.75-0.91. Weighted kappa for interobserver variation between pathologists was 0.71-0.96. Up to 20% of the cases were differently classified as positive or negative by any pathologist compared with consensus score using ≥1% positive tumor cells as cutoff. A significantly better agreement between pathologists was seen using ≥50% as cutoff (0-5% of cases). In conclusion, the concordance between the PD-L1 antibodies 22C3, 28-8 and SP263 is relatively good when evaluating lung cancers and suggests that any one of these assays may be sufficient as basis for decision on treatment with nivolumab, pembrolizumab, and durvalumab. The scoring of the pathologist presents an intrinsic source of error that should be considered especially at low PD-L1 scores.

High SMAD4 levels appear in microsatellite instability and hypermethylated colon cancers, and indicate a better prognosis.

Colorectal cancer (CRC) is one of the most common causes of cancer-related deaths in western countries. CRC are commonly divided in cancers showing microsatellite stability (MSS) or microsatellite instability (MSI). A more novel classification is dependent on promoter hypermethylation of CpG islands (the CpG island methylator phenotype, CIMP), where cancers show high, low or negative methylation status. SMAD4, located on chromosome 18q, has been thoroughly investigated during the last years. Loss of SMAD4 expression has been reported to correlate with poor CRC patient prognosis. In this study, we analyze the impact of SMAD4 expression on prognosis in relation to MSI screening status and CIMP status. Four hundred and seventy-nine paraffin-embedded specimens of CRC were examined for nuclear SMAD4 expression using immunohistochemistry. The tumors were scored loss (-), moderate (+) and high (++) expressing tumors. Loss of SMAD4 correlated significantly with decreased survival in all colon cancer patients. High SMAD4 expression, however, was significantly associated with increased survival, especially in colon cancer patients, which has undergone potential curative surgery. In addition, in MSI tumors and CIMP-high tumors, high SMAD4 expression was significantly related to increase in survival, while loss of SMAD4 resulted in a significantly poorer prognosis. SMAD4 expression was not correlated to prognosis in rectal cancer cases. We conclude, loss of SMAD4 indicates a poor prognosis in colon cancer patients. The novel findings that high SMAD4 expression predicts a better prognosis suggests that SMAD4 immunohistochemistry could constitute a prognostic marker in combination with CIMP and MSI screening status.

ErbB 1-4 expression alterations in primary colorectal cancers and their corresponding metastases.

BACKGROUND: EGFR (epidermal growth factor receptor) targeted therapies are important new tools in colorectal cancer treatment. EGFR analysis of the primary tumour was previously recommended to identify patients who will benefit from the EGFR targeted therapy. Previous studies have displayed diverging results regarding the expression of EGFR in the primary tumour compared to the metastases. The present study was performed to investigate whether EGFR and ErbB2-4 expression differed between 64 primary tumours and their corresponding metastases. PATIENTS AND METHODS: EGFR and ErbB2-4 expression were analysed in the primary tumour and in the corresponding metastases using immunohistochemistry (IHC). RESULTS: In 49/64 samples (76%), the primary tumours were EGFR positive; in 33% (16/49) of EGFR positive samples, the tumours lost the EGFR expression in the metastasis compared to the primary tumour. From the primary tumours, 15/64 (23%) were negative and 5 of these (33%) developed EGFR expression in the metastasis. ErbB2, ErbB3, and ErbB4 expression was evident in 54%, 67%, and 81%, respectively. There was no significant difference between ErbB2, ErbB3, and ErbB4 expression in primary tumours and metastases. The co-expression of the ErbB family members was also analysed, with a significant increase of ErbB3/ErbB4 co-expression in late stage tumours. CONCLUSION: The EGFR expression was lost in 33% of metastasising primary colorectal cancer tumours, a finding that agrees with at least one previous study. Thus, the present results clearly implicate the need for EGFR analysis of both the primary tumour and metastases to accurately determine EGFR status when considering the use of EGFR targeted therapies.

c-Met expression in primary tumors and their corresponding distant metastases.

c-Met is a receptor tyrosine kinase that has been implicated in the pathogenesis and growth of a wide variety of human malignancies, including CRC, but its role in metastasis is largely unknown. We compared c-Met expression in primary human colorectal carcinomas and distant metastases from the same patients. Formalin-fixed paraffin-embedded tissue samples from 69 colorectal cancer patients were obtained. The protein expression of c-Met was evaluated immunohistochemically using a commercial antibody. The difference in expression between primary tumors and their corresponding distant metastases was analyzed using the Wilcoxon signed-rank test. c-Met expression was statistically significantly lower in the distant metastases compared to their corresponding primary tumors (p<0.001), whereas no difference was found between lymph node metastases and their corresponding primary tumors (p=0.957). The degree of c-Met expression was not related to clinicopathological characteristics such as tumor grade and Dukes' stage at the time of primary tumor diagnosis, or to the location of the distant metastases. We demonstrated that c-Met expression is often reduced in distant metastases compared to their corresponding primary colorectal tumors. Additional studies of c-Met activation and signal transduction will increase our knowledge about the role of c-Met in colorectal cancer metastasis.

SMAD4/DPC4 expression and prognosis in human colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is one of the most common malignancies in Western countries. One major event during CRC development is loss of genetic material on chromosome 18, on which the smad4/dpc4 gene is located. SMAD4 is an important mediator of intracellular signaling in the TGF-beta pathway. The functional inactivation of SMAD4 has been reported to occur in CRC. MATERIALS AND METHOD: The protein expression of SMAD4 was evaluated immunohistochemically in 86 formalin-fixed and paraffin-embedded CRC samples. The results were related to clinicopathological variables including survival. RESULTS: The loss of nuclear SMAD4 protein expression was observed in 9.3% of the investigated CRCs and was correlated to poor prognosis in univariate Kaplan-Meier (p=0.034) as well as in multivariate Cox-regression (p=0.028) analyses. CONCLUSION: The loss of nuclear SMAD4 protein expression occurs in a subset of CRC and is associated with poor prognosis.