Retrospective Comparative Analysis of KRAS G12C vs. Other KRAS Mutations in mCRC Patients Treated With First-Line Chemotherapy Doublet + Bevacizumab.

BACKGROUND: KRAS mutations in metastatic colorectal cancer (mCRC) define a subset of tumors that have primary resistance to anti-EGFR-based therapy. Data concerning whether different KRAS mutations may also have a prognostic value are lacking. Furthermore, novel KRAS G12C inhibitors are currently in development. The aim of our analysis was to compare response rates in patients treated with first-line chemotherapy doublet + Bevacizumab among different KRAS variants. Secondary end-points were progression free survival (PFS) and overall survival (OS). METHODS: Patients with KRAS mutated mCRC treated with either FOLFIRI/FOLFOX/XELOX + Bevacizumab were eligible for enrollment. Patients whose tumor harbored NRAS mutations or that coexpressed also BRAF mutations were excluded from this retrospective analysis. Patients' individual data were collected from patients' records. Propensity score matching (nearest method, 1:2 ratio) was used to define the two different groups of patients for comparison (KRAS G12C mutated vs other KRAS variants). Eastern Cooperative Oncology Group Performance Status (ECOG PS), sex, metastatic site of involvement, synchronous vs metachronous metastatic disease, tumor sidedness, mucinous histology, primary tumor surgery, more than two lines of treatment for metastatic disease, and radical surgery of metastases were used as matching factors. Response rate (RR) was calculated by RECIST 1.1 criteria. Both progression free-survival and overall survival were calculated by Kaplan-Meier method. Categorical variables were compared by Fisher exact test for binomial variables and by chi-square test for all other instances. The level of statistical significance p was set at 0.05 for all tests. RESULTS: A total of 120 patients were assessed in the final analysis. Out of the 120 patients, 15 (12%) were KRAS G12C mutated. In the whole cohort of patients, 59/120 (49%) had partial response (PR), 42/120 (35%) had stable disease (SD), and 19/120 (16%) had progressive disease (PD) as the best response. In KRAS G12C patients, 4/15 (27%) had PR, 6/15 (40%) had SD, and the remaining 5/15 (33%) had PD as the best response. In patients with other KRAS mutations, 55/105 (52%) had PR, 37/105 (35%) had SD, and the remaining 13/105 (12%) had PD as the best response. The difference in RR between the two groups of patients was statistically significant (p=0.017). On the other hand, no difference in PFS (p=0.76) and OS (p=0.56) was observed. After matching procedures, the difference in response rates between KRAS G12C mutated patients vs the matched cohort of patients with other KRAS mutations remained statistically significant (p=0.016). KRAS G12C mutations were not associated with differences in sites of metastatic involvement, sex, and ECOG PS. On the other hand, synchronous vs metachronous metastatic disease (p=0.039), age > 75 years (p=0.043), and mucinous histology (p=0.008) were more frequent in G12C mutated tumors. CONCLUSIONS: In our cohort of patients, it was observed that KRAS G12C mutations are associated with worse response rates compared to other KRAS variants when treated with standard chemotherapy doublet + Bevacizumab. On the other hand, both PFS and OS were not significantly different. Based on these findings, we believe that new treatment options focused on KRAS G12C inhibition should be tested mainly in first-line setting and in addition to standard chemotherapy doublet + Bevacizumab for mCRC patients, as they might "fill the gap" in response rates that was seen in our study.

Retrospective Cohort Study of Caveolin-1 Expression as Prognostic Factor in Unresectable Locally Advanced or Metastatic Pancreatic Cancer Patients.

Caveolin-1 (Cav-1) plays a key role in various neoplastic diseases and is upregulated in different cancers, including pancreatic ductal adenocarcinoma (PDAC). Furthermore, Cav-1 is critical for the uptake of albumin as well as nab-paclitaxel in PDAC cells. Here, we investigated the prognostic impact of Cav-1 expression in a cohort of 39 metastatic PDAC patients treated with different first-line chemotherapy regimens. We also assessed the predictive value of Cav-1 in patients treated with gemcitabine and nab-paclitaxel. Cav-1 expression was evaluated by immunohistochemistry staining in neoplastic and stromal cells, using metastatic sites or primary tumor tissue specimens. Higher levels of Cav-1 expression were associated with significantly worse overall survival (OS) and progression-free survival (PFS). No differences in OS were found between patients treated with gemcitabine + nab-paclitaxel vs. other chemotherapy options. Multivariate analysis for OS and PFS confirmed the independent prognostic role of Cav-1 expression. Our study evidenced a negative prognostic role of Cav-1 in patients affected by metastatic/locally advanced unresectable PDAC. Moreover, Cav-1 expression seems not to predict different response rates to different types of first-line treatment. Future prospective trials will be necessary to confirm the prognostic role of Cav-1 and explore Cav-1 specific inhibitors as a therapeutic option for advanced PDAC patients.

An observational retrospective analysis of the main metastatic site and corresponding locoregional treatment as a prognostic factor in metastatic gastric cancer.

Despite novel drugs, the prognosis for patients with metastatic gastric cancer remains poor. In rare instances, locoregional therapies are used in addition to standard chemotherapy in patients with oligometastatic involvement. This type of approach has not been supported by solid published evidence. The aim of the present retrospective study was to assess the prognostic impact of factors such as metastatic site, tumour histology and locoregional treatment in patients with metastatic gastric cancer. A total of 184 patients with metastatic gastric or gastroesophageal junction adenocarcinoma who received at least one line of palliative therapy with doublet or triplet chemotherapy were enrolled in the current analysis. Median overall survival (OS) was 8.32 months (95% CI, 7.02-9.41) and median progression-free survival (PFS) was 4.16 months (95% CI, 3.24-5.08). Lung metastases vs. other sites of metastatic involvement [hazard ratio (HR), 0.27; P=0.0133] and intestinal histology (HR, 0.48; P=0.08) were significantly associated with an improved OS. Improved PFS was also observed (HR, 0.49; P=0.10 and HR, 0.72; P=0.08 for lung metastases and intestinal histology, respectively). Second line chemotherapy and locoregional treatment of metastases (surgery or radiotherapy) were associated with improved OS (HR, 0.52; P<0.0001 and HR, 0.35; P<0.0001, respectively). Multivariate analysis confirmed an independent prognostic role for OS only for locoregional treatment, second line treatment and intestinal histology. The present results suggested that the presence of lung metastases alone was not a relevant prognostic factor and was influenced by the availability of further lines of treatment or by locoregional treatments. Locoregional treatments in patients with oligometastatic disease should be offered as they allow prolonged survival in patients with otherwise relatively short life expectancy.

Seminoma Retroperitoneal Relapse 23 Years After Surgery.

Stage I seminoma is the most frequent tumour in young men. It has a very good prognosis thanks to the use of a multidisciplinary therapeutic approach including surgery, radiotherapy and systemic chemotherapy. Late (after 2 years) and very late (after 5 years) relapses are uncommon, but not impossible, even if standardized follow-up for testicular tumours lasts up to 5 years after the diagnosis. We report a case of a 67-year-old Caucasian man with metachronous bilateral testicular seminoma who developed a retroperitoneal relapse of testicular seminoma 23 years after the first orchiectomy. Based on histological confirmation of testicular relapse, the patient underwent four cycles of systemic chemotherapy with bleomycin, etoposide and cisplatin (PEB), with no adverse reactions. He subsequently achieved complete radiological response at restaging computed tomography imaging, confirmed by the absence of glucose metabolism on positron emission tomography. In conclusion, this case report suggests the importance of longer standardized follow-up for patients treated for testicular tumours in order to detect earlier recurrence, which can be successfully treated.

Lynch syndrome-associated lung cancer: pitfalls of an immunotherapy-based treatment strategy in an unusual tumor type.

Lynch syndrome is a hereditary cancer predisposition syndrome caused by germline alterations in mismatch repair (MMR) genes leading to increased risk of colon cancer as well as other cancer types. Non-small cell lung cancer (NSCLC) is not among typical Lynch syndrome-associated tumors: pembrolizumab, an immune checkpoint inhibitor, is actually approved for the treatment of NSCLC patients and represents a promising treatment option for patients with advanced metastatic MMR-deficient cancer, regardless of tumor origin. This case report describes the clinical presentation and management of a 74-year-old female with a history of rectal adenocarcinoma and ovarian cancer, who has a documented frameshift pathogenic variant in the exon 8 of MSH6 gene and an intronic variant in the BRCA2 gene (classified as a variant of uncertain significance), affected by NSCLC with brain metastases. Despite these premises, the patient was treated with pembrolizumab and she did not benefit from this kind of treatment.

Bullous Sweet's syndrome in a patient with ulcerative colitis: a rare case report.

Bullous Sweet's syndrome is an uncommon clinical presentation of classical Sweet's syndrome, often associated with various kinds of tumors, infections, and active inflammatory bowel diseases (IBDs), namely Crohn's disease and ulcerative colitis. Only a few cases of bullous Sweet's syndrome associated with ulcerative colitis are described in the literature. We report a case of a 62-year-old female patient with acute exacerbation of ulcerative colitis associated with infiltrating purple-erythematous skin plaques, which were partly vesicular, and oral ulcerative stomatitis. Biopsy was consistent with bullous Sweet's syndrome. Treatment with betamethasone sodium phosphate, starting at 5.5 mg, followed by gradual dose tapering for 12 weeks, resulted in improvement of the ulcerative colitis and disappearance of the cutaneous lesions. Bullous Sweet's syndrome most commonly occurs in the setting of hematologic malignancies, suggesting that physicians should perform long-term screening for early diagnosis of hematological and solid malignancies.

Liver transplantation for metastatic wild-type gastrointestinal stromal tumor in the era of molecular targeted therapies: Report of a first case.

The gastrointestinal stromal tumor (GIST) is a digestive neoplasm of mesenchymal lineage. The treatment strategy for receptor tyrosine kinase-mutated GISTs is well defined. Wild-type GISTs (WT-GISTs) respond unsatisfactorily to specific kinase inhibitors. Moreover, evidence shows that repeat surgery has limited benefit. We report the case of a young female patient who was diagnosed with liver metastatic WT-GIST, after initial radical resection and adjuvant therapy with molecular targeted drugs. Due to the disease progression, a two-stage surgery was performed, with the removal of extrahepatic lesions followed by a total hepatectomy. The patient is disease-free after 4 years from liver transplantation (LT), performed under everolimus-based immunosuppression. The treatment of WT-GISTs remains a significant challenge due to the frequent resistance to tyrosine kinase inhibitors (TKIs). Liver transplantation might represent an effective treatment option for such disease.

Mycophenolate mofetil-induced colitis in a patient with systemic sclerosis.

We present the case of a 44-year-old woman affected by systemic sclerosis (SSc) who was admitted to our department for abdominal pain, nausea, vomiting and fever. Imaging studies showed the presence of a thickened colon wall involving the descending colon and the sigma, while a subsequent endoscopy revealed multiple serpiginous ulcers covered with fibrin and exudates. Under the hypothesis of drug-induced colitis, mycophenolate mofetil (MMF), which she was taking for SSc-related interstitial lung disease (ILD), was readily suspended, with a rapid recovery without further treatment. A follow-up colonoscopy showed the complete resolution of the ulcers. This is the first case of MMF-induced colitis in a patient being treated for SSc-ILD.

Neurofibromin C terminus-specific antibody (clone NFC) is a valuable tool for the identification of NF1-inactivated GISTs.

An increasing body of evidence supports the involvement of NF1 mutations, constitutional or somatic, in the pathogenesis of gastrointestinal stromal tumors (GISTs). Due to the large size of the NF1 locus, the existence of multiple pseudogenes and the wide spectrum of mechanisms of gene inactivation, the analysis of NF1 gene status is still challenging for most laboratories. Here we sought to assess the efficacy of a recently developed neurofibromin-specific antibody (NFC) in detecting NF1-inactivated GISTs. NFC reactivity was analyzed in a series of 98 GISTs. Of these, 29 were 'NF1-associated' (17 with ascertained NF1 mutations and 12 arising in the context of clinically diagnosed Neurofibromatosis type 1 syndrome and thus considered bona fine NF1 inactivated); 38 were 'NF1-unrelated' (either wild-type or carrying non-pathogenic variants of NF1). Thirty-one additional GISTs with no available information on NF1 gene status or with NF1 gene variants of uncertain pathogenic significance were also included in the analysis. Cases were scored as NFC negative when, in the presence of NFC positive internal controls, no cytoplasmic staining was detected in the neoplastic cells. NFC immunoreactivity was lost in 24/29 (83%) NF1-associated GISTs as opposed to only 2/38 (5%) NF1-unrelated GISTs (P=3e-11). NFC staining loss significantly correlated (P=0.007) with the presence of biallelic NF1 inactivation, due essentially to large deletions or truncating mutations. NFC reactivity was instead retained in two cases in which the NF1 alteration was heterozygous and in one case where the pathogenic NF1 variant, although homo/hemizygous, was a missense mutation predicted not to affect neurofibromin half-life. Overall this study provides evidence that NFC is a valuable tool for identifying NF1-inactivated GISTs, thus serving as a surrogate for molecular analysis.

A germline missense mutation in exon 3 of the MSH2 gene in a Lynch syndrome family: correlation with phenotype and localization assay.

Lynch syndrome is caused by germline mutations in any of the MisMatch Repair (MMR) genes. About 37% of MSH2 variants are missense variants causing single amino-acid substitutions. Whether missense variants affect the normal function of MMR proteins is crucial both to provide affected families a more accurate risk assessment and to offer predictive testing to family members. Here we report one family, fulfilling both Amsterdam I and II criteria and Bethesda guidelines, referred to our center for genetic counselling. The proband and some of her relatives have been investigated for microsatellite instability (MSI), immunohistochemical MMR protein staining, direct sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA). Also Subcellular Localization Assay and Splice site predictions analyses were used. A germline missense variant of uncertain significance (exon 3, p.Val161Asp) was found in MSH2 gene in proband and in some relatives. The variant was associated with lack of expression of MSH2 protein (DMMR) and MSI-High status in tumour tissues. The localization assay of the MSH2 protein showed an abnormal subcellular localization pattern of the corresponding protein. Finally, splice-site prediction analysis ruled out a potential role of new splice sites as the cause behind the lack of expression of MSH2 protein and we suppose a potential correlation with other forms of post-transcriptional regulation (circular RNAs). The variant here reported shows a high correlation with phenotype and is located in an evolutionary conserved domain. The localization assay also suggest a potential pathogenic role, thus supporting further research on this matter.

ROC-king onwards: intraepithelial lymphocyte counts, distribution & role in coeliac disease mucosal interpretation.

OBJECTIVES: Counting intraepithelial lymphocytes (IEL) is central to the histological diagnosis of coeliac disease (CD), but no definitive 'normal' IEL range has ever been published. In this multicentre study, receiver operating characteristic (ROC) curve analysis was used to determine the optimal cut-off between normal and CD (Marsh III lesion) duodenal mucosa, based on IEL counts on >400 mucosal biopsy specimens. DESIGN: The study was designed at the International Meeting on Digestive Pathology, Bucharest 2015. Investigators from 19 centres, eight countries of three continents, recruited 198 patients with Marsh III histology and 203 controls and used one agreed protocol to count IEL/100 enterocytes in well-oriented duodenal biopsies. Demographic and serological data were also collected. RESULTS: The mean ages of CD and control groups were 45.5 (neonate to 82) and 38.3 (2-88) years. Mean IEL count was 54±18/100 enterocytes in CD and 13±8 in normal controls (p=0.0001). ROC analysis indicated an optimal cut-off point of 25 IEL/100 enterocytes, with 99% sensitivity, 92% specificity and 99.5% area under the curve. Other cut-offs between 20 and 40 IEL were less discriminatory. Additionally, there was a sufficiently high number of biopsies to explore IEL counts across the subclassification of the Marsh III lesion. CONCLUSION: Our ROC curve analyses demonstrate that for Marsh III lesions, a cut-off of 25 IEL/100 enterocytes optimises discrimination between normal control and CD biopsies. No differences in IEL counts were found between Marsh III a, b and c lesions. There was an indication of a continuously graded dose-response by IEL to environmental (gluten) antigenic influence.

Radiological response and inflammation scores predict tumour recurrence in patients treated with transarterial chemoembolization before liver transplantation.

AIM: To investigate the prognostic value of the radiological response after transarterial chemoembolization (TACE) and inflammatory markers in patients affected by hepatocellular carcinoma (HCC) awaiting liver transplantation (LT). METHODS: We retrospectively evaluated the preoperative predictors of HCC recurrence in 70 patients treated with conventional (n = 16) or doxorubicin-eluting bead TACE (n = 54) before LT. The patient and tumour characteristics, including the static and dynamic alpha-fetoprotein, neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio (PLR) measurements, were recorded. Treatment response was classified according to the modified Response Evaluation Criteria in Solid Tumours (mRECIST) and the European Association for the Study of the Liver (EASL) criteria as complete response (CR), partial response (PR), stable disease or progressive disease. After examination of the explanted livers, histological necrosis was classified as complete (100% of the cumulative tumour area), partial (50%-99%) or minimal (< 50%) and was correlated with the preoperative radiological findings. RESULTS: According to the pre-TACE radiological evaluation, 22/70 (31.4%) and 12/70 (17.1%) patients were beyond Milan and University of San Francisco (UCSF) criteria, respectively. After TACE procedures, the objective response (CR + PR) rates were 71.4% and 70.0% according to mRECIST and EASL criteria, respectively. The agreement between the two guidelines in defining the radiological response was rated as very good both for the overall and target lesion response (weighted k-value: 0.98 and 0.93, respectively). Complete and partial histological necrosis were achieved in 14/70 (20.0%) and 28/70 (40.0%) patients, respectively. Using histopathology as the reference standard, mRECIST criteria correctly classified necrosis in 72.9% (51/70) of patients and EASL criteria in 68.6% (48/70) of cases. The mRECIST non-response to TACE [Exp(b) = 9.2, p = 0.012], exceeding UCSF criteria before TACE [Exp(b) = 4.7, p = 0.033] and a preoperative PLR > 150 [Exp(b) = 5.9, p = 0.046] were independent predictors of tumour recurrence. CONCLUSION: The radiological response and inflammatory markers are predictive of tumour recurrence and allow the proper selection of TACE-treated candidates for LT.

The role of primary tumour sidedness, EGFR gene copy number and EGFR promoter methylation in RAS/BRAF wild-type colorectal cancer patients receiving irinotecan/cetuximab.

BACKGROUND: The data from randomised trials suggested that primary tumour sidedness could represent a prognostic and predictive factor in colorectal cancer (CRC) patients, particularly during treatment with anti-epidermal growth factor receptor (EGFR) therapy. However, an in-deep molecular selection might overcome the predictive role of primary tumour location in this setting. METHODS: We conducted a retrospective analysis in which tumour samples from RAS/BRAF wild-type (WT) metastatic CRC patients treated with second-third-line irinotecan/cetuximab were analysed for EGFR gene copy number (GCN) and promoter methylation. Study objective was to evaluate the correlation of tumour sidedness, EGFR promoter methylation and EGFR GCN with clinical outcome. Median follow-up duration was 14.3 months. RESULTS: Eighty-eight patients were included in the study, 27.3% had right-sided CRC, 72.7% had left-sided CRC; 36.4% had EGFR GCN<2.12 tumour, 63.6% had EGFR GCN⩾2.12 tumour; 50% had EGFR promoter-methylated tumour. Right-sided colorectal cancer (RSCRC) were associated with reduced overall response rate (ORR) (4.2% for RSCRC vs 35.9% for left sided colorectal cancer (LSCRC), P=0.0030), shorter progression-free survival (PFS) (3.0 vs 6.75 months, P<0.0001) and shorter overall survival (OS) (8 vs 13.6 months, P<0.0001). EGFR GCN<2.12 tumours were associated with reduced ORR (6.2% for EGFR GCN<2.12 vs 39.3% for EGFR GCN⩾2.12 tumours, P=0.0009), shorter PFS (3.5 vs 6.5 months, P=0.0006) and shorter OS (8.5 vs 14.0 months, P<0.0001). Epidermal growth factor receptor-methylated tumours were associated with reduced ORR (9.1% for methylated vs 45.5% for unmethylated, P=0.0001), shorter PFS (3 vs 7.67 months, P<0.0001) and shorter OS (8 vs 17 months, P<0.0001). At multivariate analysis, EGFR GCN and EGFR promoter methylation maintained their independent role for ORR (respectively P=0.0082 and 0.0025), PFS (respectively P=0.0048 and<0.0001) and OS (respectively P=0.0001 and<0.0001). CONCLUSIONS: In our study, an accurate molecular selection based on an all RAS and BRAF analysis along with EGFR GCN and EGFR promoter methylation status seems to be more relevant than primary tumour sidedness in the prediction of clinical outcome during cetuximab/irinotecan therapy. However, these data need to be validated with future prospective and translational studies.

Mismatch repair deficiency may affect clinical outcome through immune response activation in metastatic gastric cancer patients receiving first-line chemotherapy.

INTRODUCTION: The microsatellite-instable gastric cancer subtype, because of its supposed high antigenic potential, is a promising candidate for immunotherapy. We analyzed if the presence of a defective mismatch repair (MMR) system is associated with other markers of immune response and their relationship with outcome in advanced gastric cancer patients. METHODS: We analyzed the relationship between clinical outcome and MMR status, the presence of tumor-infiltrating lymphocytes (TIL), lymphocytosis, and neutrophil-to-lymphocyte ratio (NLR) in metastatic gastric cancer patients treated with a chemotherapy doublet in the first-line setting. Other stratification factors were sex, age, Eastern Cooperative Oncology Group performance status, adjuvant/neoadjuvant chemotherapy, metastatic sites, and histotype. RESULTS: One hundred three patients were eligible for analysis. Defective MMR was found in 15 patients (14 %), TILs were found in 18 patients (17 %), lymphocytosis was found in 24 patients (23 %), and high NLR was found in 75 patients (72 %). Significant correlations were found between defective MMR and TIL positivity (p = 0.0004), between defective MMR and lymphocytosis (p = 0.0062), between defective MMR and low NLR (p = 0.000069), and between TIL positivity and lymphocytosis (p = 0.000147). All factors had a statistically significant impact on overall survival, although on multivariate analysis only defective MMR (p = 0.0001) and TIL positivity (p = 0.0192) maintained their independent prognostic role. Similar results were observed for progression-free survival, with defective MMR (p = 0.0001) and TIL positivity (p = 0.0195) maintaining their prognostic role on multivariate analysis. CONCLUSIONS: Our analysis confirms the favorable prognosis of metastatic gastric cancer patients with a defective MMR system and suggests that expression of TILs might also be linked to better outcome. Because of the correlation between defective MMR status and measures of immune system activity, this group of patients would be the best candidates for novel immunotherapy-based therapies.

Quadruple-Negative GIST Is a Sentinel for Unrecognized Neurofibromatosis Type 1 Syndrome.

PURPOSE: The majority of gastrointestinal stromal tumors (GIST) are driven by KIT, PDGFRA, or, less commonly, BRAF mutations, and SDH gene inactivation is involved in a limited fraction of gastric lesions. However, about 10% of GISTs are devoid of any of such alterations and are poorly responsive to standard treatments. This study aims to shed light on the molecular drivers of quadruple-negative GISTs. EXPERIMENTAL DESIGN: Twenty-two sporadic quadruple-negative GISTs with no prior association with Neurofibromatosis Type 1 syndrome were molecularly profiled for a panel of genes belonging to tyrosine kinase pathways or previously implicated in GISTs. For comparison purposes, 24 GISTs carrying KIT, PDGFRA, or SDH gene mutations were also analyzed. Molecular findings were correlated to clinicopathologic features. RESULTS: Most quadruple-negative GISTs featured intestinal localization, with a female predilection. About 60% (13/22) of quadruple-negative tumors carried NF1 pathogenic mutations, often associated with biallelic inactivation. The analysis of normal tissues, available in 11 cases, indicated the constitutional nature of the NF1 mutation in 7 of 11 cases, unveiling an unrecognized Neurofibromatosis Type 1 syndromic condition. Multifocality and a multinodular pattern of growth were common findings in NF1-mutated quadruple-negative GISTs. CONCLUSIONS: NF1 gene mutations are frequent in quadruple-negative GISTs and are often constitutional, indicating that a significant fraction of patients with apparently sporadic quadruple-negative GISTs are affected by unrecognized Neurofibromatosis Type 1 syndrome. Hence, a diagnosis of quadruple-negative GIST, especially if multifocal or with a multinodular growth pattern and a nongastric location, should alert the clinician to a possible Neurofibromatosis Type 1 syndromic condition. Clin Cancer Res; 23(1); 273-82. ©2016 AACR.

Are liver nested stromal epithelial tumors always low aggressive?

Nested stromal-epithelial tumor (NSET) is a non-hepatocytic and non-biliary tumor of the liver consisting of nests of epithelial and spindled cells with associated myofibroblastic stroma and variable intra-lesional calcification and ossification, which represents a very rare and challenging disease. Most of the reported cases have been treated with surgery, obtaining a long survival outcome. Here, we report the case of a 31-year-old Caucasian man who underwent surgery at our institution for a large, lobulated, multinodular mass of the right hemi-liver. The histological exam confirmed the diagnosis of NSET. After 6 mo from surgery, a liver recurrence was described and a chemo-embolization was performed. After a further disease progression, based on the correlation between the histological features of the disease and those of the hepatoblastoma, a similar chemotherapy regimen (with cisplatin and ifosfamide/mesna chemotherapy, omitting doxorubicin due to liver impairment) was administered. However, infection of the biliary catheter required a dose modification of the treatment. No benefit was noted and a progression of disease was radiologically assessed after only four cycles. The worsening of the clinical status prevented further treatments, and the patient died a few months later. This case report documents how the NSET might have an aggressive and non-preventable behavior. No chemotherapy schedules with a proved efficacy are available, and new data are needed to shed light on this rare neoplasm.

Concomitant KIT/BRAF and PDGFRA/BRAF mutations are rare events in gastrointestinal stromal tumors.

AIM: The BRAF mutation is a rare pathogenetic alternative to KIT/PDGFRA mutation in GIST and causes Imatinib resistance. A recent description of KIT and BRAF mutations co-occurring in an untreated GIST has challenged the concept of their being mutually exclusive and may account for ab initio resistance to Imatinib, even in the presence of Imatinib-sensitive KIT mutations. BRAF sequencing is generally limited to KIT/PDGFRA wild-type cases. Hence, the frequency of concomitant mutations may be underestimated. METHODS: We screened for KIT (exon 9, 11 ,13 ,17), PDGFRA (exon 12,14, 18) and BRAF (exon 15) mutations a series of 407 GIST. Additionally, we evaluated the BRAF V600E mutation-specific antibody, VE1, as a surrogate for V600E mutation, on a series of 313 GIST (24 on whole sections, 288 cases on tissue array), including 6 cases molecularly ascertained to carry the BRAF V600E mutation. RESULTS: No concomitant KIT/BRAF or PDGFRA/BRAF mutations were detected. BRAF mutation was detected only in one case, wild-type for KIT/PDGFRA. All the 6 BRAF-mutant cases stained positive with the VE1 antibody. A weak VE1 expression was observed in 14/287 (4.9%) BRAF wild-type cases, as observed also in 2/6 BRAF-mutant cases. Overall in our series, sensitivity and specificity of the VE1 antobody were 100% and 95.1%, respectively. CONCLUSIONS: The concomitance of BRAF mutation with either KIT or PDGFRA mutation is rare in GIST. In these tumors, moderate/strong VE1 immunoreactivity is a valuable surrogate for molecular analysis. Instead, genotyping is warranted in the presence of weak VE1 staining.

KRAS mutation status is associated with specific pattern of genes expression in pancreatic adenocarcinoma.

AIMS: To evaluate potential differences at a molecular level between KRAS mutant tumors (MT) and KRAS wild-type (WT) pancreatic tumors and the biological and prognostic significance of different KRAS mutations. MATERIALS & METHODS: Expression of a panel of 29 genes was analyzed in KRAS WT and MT tumors. Effects of KRAS mutation and gene expression levels were assessed on patients' survival. RESULTS: MUC6 (p = 0.009), HGF (p = 0.011), VEGFR-2 (p = 0.020) and VEGFB (p = 0.026) were significantly more expressed and SMAD4 was less suppressed (p = 0.003) in WT KRAS. Contrariwise, SHH (p = 0.012) and IHH (p = 0.031) were more expressed in MT KRAS patients. No OS difference was found between WT and MT KRAS tumors. CONCLUSION: KRAS mutation status seems to identify two different subtypes of pancreatic ductal adenocarcinoma with similar outcome but distinct molecular features and probably different therapeutic targets.

HER family receptor expression and prognosis in pancreatic cancer.

BACKGROUND: HER family receptors play a key role in tumor progression in several malignancies, such as colorectal, lung or breast cancer. The aims of this study were to investigate expression of HER-1, HER-2 and HER-3 in pancreatic cancer (PC) samples and evaluate the association between HER-family receptor expression and patients' clinical outcomes. METHODS: Tissue samples from 91 PC patients were subjected to immunohistochemical staining to assess the expression of HER-1, HER-2 and HER-3. Semiquantitative scores of zero (no staining or staining in less than 10% of cancer cells), 1+, 2+ or 3+ were assigned to each sample based on the intensity of staining for HER receptors. Scores of 2+ or 3+ were defined as positive staining. RESULTS: HER-1 overexpression was observed in 41 out of 91 samples (45.1%), while HER-2 was not overexpressed in any of the analyzed samples. HER-3 was overexpressed in 37 samples (40.7%) and was found to be associated with advanced TNM stage. In particular, HER-3 was overexpressed in 12 out of 16 stage IV patients (75%) compared with only 33.3% of stage I-III patients (p = 0.02). Among 79 patients with available survival data, the 6 patients with strong HER-3 expression (score 3+) had a shorter survival compared with remaining patients (median overall survival 6.9 months vs. 12.3 months, respectively). CONCLUSIONS: HER-1 and HER-3 were found to be expressed in a significant proportion of PC patients. Strong HER-3 expression represents an indicator of poor prognosis in PC patients, being associated with advanced stage and shorter survival.