KIT, PDGFRA, and BRAF mutational spectrum impacts on the natural history of imatinib-naive localized GIST: a population-based study.

The mutation status of KIT or PDGFRA notoriously affects the response of advanced gastrointestinal stromal tumors (GISTs) to tyrosine kinase inhibitors. Conversely, it is currently still unclear whether mutation status impinges on the prognosis of localized, untreated GISTs. Hence, at present, this variable is not included in decision making for adjuvant therapy. A series of 451 primary localized GISTs were analyzed for KIT, PDGFRA, and BRAF mutations. Univariable and multivariable analyses and a backward selection procedure were used to assess the impact of mutation status on overall survival and to identify prognostically homogenous groups. Mutation was a significant prognostic indicator of overall survival in naive, localized GISTs (P<0.001): KIT-mutated patients had a worse outcome than PDGFRA-mutated or triple-negative (KIT, PDGFRA, BRAF wild-type) cases. Multivariable Cox regression models allowed us to identify 3 molecular risk groups: group I exhibited the best outcome and included PDGFRA exon 12, BRAF, and KIT exon 13-mutated cases; group II, of intermediate clinical phenotype (HR=3.06), included triple-negative, KIT exon 17, PDGFRA exon 18 D842V, and PDGFRA exon 14-mutated cases; group III displayed the worst outcome (hazard ratio=4.52), and comprised KIT exon 9 and exon 11 and PDGFRA exon 18 mutations apart from D842V. This study highlights the prognostic impact of mutation status on the natural course of GIST and suggests that the molecular prognostic grouping may complement the conventional clinicopathologic risk stratification criteria in decision making for adjuvant therapy.

VEGF and VEGFR genotyping in the prediction of clinical outcome for HCC patients receiving sorafenib: the ALICE-1 study.

Although new treatment modalities changed the global approach to hepatocellular carcinoma (HCC), this disease still represents a medical challenge. Currently, the therapeutic stronghold is sorafenib, a tyrosine kinase inhibitor (TKI) directed against the vascular endothelial growth factor (VEGF) family. Previous observations suggested that polymorphisms of VEGF and its receptor (VEGFR) genes may regulate angiogenesis and lymphangiogenesis and thus tumour growth control. The aim of our study was to evaluate the role of VEGF and VEGFR polymorphisms in determining the clinical outcome of HCC patients receiving sorafenib. From a multicentre experience 148 samples (tumour or blood samples) of HCC patients receiving sorafenib were tested for VEGF-A, VEGF-C and VEGFR-1,2,3 single nucleotide polymorphisms (SNPs). Patients' progression-free survival (PFS) and overall survival (OS) were analysed. At univariate analysis VEGF-A alleles C of rs25648, T of rs833061, C of rs699947, C of rs2010963, VEGF-C alleles T of rs4604006, G of rs664393, VEGFR-2 alleles C of rs2071559, C of rs2305948 were significant predictors of PFS and OS. At multivariate analysis rs2010963, rs4604006 and BCLC (Barcelona Clinic Liver Cancer) stage resulted to be independent factors influencing PFS and OS. Once prospectively validated, the analysis of VEGF and VEGFR SNPs may represent a clinical tool to better identify HCC patients more likely to benefit from sorafenib. On the other hand, the availability of more accurate predictive factors could help avoiding unnecessary toxicities to potentially resistant patients who may be optimal candidates for different treatments interfering with other tumour molecular pathways.

Pulmonary tumor thrombotic microangiopathy: the challenge of the antemortem diagnosis.

Pulmonary tumor thrombotic microangiopathy (PTTM) is known as a rare and severe cancer-related pulmonary complication. Nowadays, fewer than 80 cases have been reported in the literature and very few cases have been diagnosed antemortem. We describe an autopsy case of PTTM associated with cancer of unknown origin. A 56-year-old male patient came to our attention due to a 2-day history of dyspnea. Analysis of the clinical context in combination with laboratory and imaging tests led us to suspect acute pulmonary thromboembolism. However, the computed tomography pulmonary angiogram was negative for thromboembolism; on the contrary it revealed multiple lymphadenopathy. Microscopic pulmonary tumor embolism was suspected and a lymph node biopsy was planned. However, the patient's condition progressively worsened; death occurred 3 days after admission. After autopsy, histologically extensive neoplastic emboli involved the small pulmonary arteries and arterioles, often admixed with fibrin thrombi. The involved and noninvolved arteries also demonstrated fibrocellular intimal proliferation causing marked luminal stenosis and occlusion. These pathological features were characteristic of PTTM, which should be distinguished from microscopic tumor embolism and should be considered in the differential diagnosis of acute/subacute cor pulmonale and pulmonary hypertension in cancer as well as in noncancer patients. We propose a review of the literature and an algorithm to improve PTTM antemortem diagnosis.

Clinical evidence for three distinct gastric cancer subtypes: time for a new approach.

BACKGROUND: Recently, a new classification for gastric cancer (GC) has been proposed, based on Lauren's histology and on anatomic tumour location, identifying three subtypes of disease: type 1 (proximal non diffuse GC), type 2 (diffuse GC) and type 3 (distal non diffuse GC). Aim of our analysis was to compare clinical outcome according to different GC subtypes (1,2,3) in metastatic GC patients receiving first-line chemotherapy. PATIENTS AND METHODS: Advanced GC pts treated with a first-line combination chemotherapy were included in our analysis. Pts were divided in three subgroups (type 1, type 2 and type 3) as previously defined. RESULTS: A total of 248 advanced GC pts were included: 45.2% belonged to type 2, 43.6% to type 3 and 11.2% to type 1. Patients received a fluoropyrimidine-based chemotherapy doublet or three drugs regimens including a platinum derivate and a fluoropyrimidine with the addition of an anthracycline, a taxane or mytomicin C. RR was higher in type 1 pts (RR = 46.1%) and type 3 (34,3%) compared to type 2 (20,4%), (p = 0.015). Type 2 presented a shorter PFS, median PFS = 4.2 months, compared to type 1, mPFS = 7.2 months, and type 3, mPFS = 5.9 months (p = 0.011) and also a shorter OS (p = 0.022). CONCLUSIONS: Our analysis suggests that GC subtypes may be important predictors of benefit from chemotherapy in advanced GC patients. Future clinical trials should take in account these differences for a better stratification of patients.

Tumor angiogenesis genotyping and efficacy of first-line chemotherapy in metastatic gastric cancer patients.

AIM: Besides correlating with prognosis, tumor-driven angiogenesis also seemed able to influence response/resistance to chemotherapy in preclinical models. We examined the role of tumor angiogenesis genotyping in determining clinical outcome in metastatic gastric cancer patients receiving first-line chemotherapy. PATIENTS & METHODS: VEGF-A, VEGF-C, FLT1, KDR and FLT4 genotyping was analyzed in gastric tumors from patients receiving platinum-based first-line chemotherapy. RESULTS: VEGF-A rs25648 correlated with response rate (partial response: 18% among patients showing the VEGF-A rs25648 CT or TT genotype vs 44% among patients showing the VEGF-A rs25648 C genotype; p = 0.04). At multivariate analysis only VEGF-A rs25648 maintained an independent role in determining median progression-free survival (hazard ratio: 1.65 95% CI: 1.12-2.78) and overall survival (hazard ratio: 1.58, 95% CI: 1.17-2.65). CONCLUSION: VEGF-A rs25648 genotyping may help identify a patient subgroup unlikely to benefit from a first-line, platinum-based combination and potential candidates for alternative therapy choices.

Doxorubicin-eluting bead vs conventional transcatheter arterial chemoembolization for hepatocellular carcinoma before liver transplantation.

AIM: To assess the possible effect of two different types of preoperative transcatheter arterial chemoembolization (TACE) on recurrence-free survival after liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) and to analyze the effects of TACE on tumor histology. METHODS: We retrospectively analyzed the histological features of 130 HCC nodules in 63 native livers removed at transplantation. Patients who received any other type of treatment such as radiofrequency tumor ablation, percutaneous ethanol ablation or who were not treated at all were excluded. All patients in the present study were within the Milan Criteria at the last imaging findings before transplantation. Doxorubicin-eluting bead TACE (DEB-TACE) was performed in 22 patients (38 nodules), and conventional TACE (c-TACE) in 16 (25 nodules). Patients' and tumors' characteristics were retrospectively reviewed. We performed a per-nodule analysis of the explanted livers to establish the mean percentage of necrosis of any nodule treated by TACE (conventional or DEB) and a per-patient analysis to establish the percentage of necrosis in the cumulative tumor area, including 21 nodules not reached by TACE. Inflammatory and fibrotic changes in the tissue surrounding the tumor nodule were analyzed and categorized as poor/absent, moderate and enhanced reaction. Uni- and multivariate analysis of risk factors for HCC-recurrence were performed. RESULTS: The number and diameter of the nodules, the time spent on the waiting list and the number of treatments were similar in the two groups. A trend towards higher appropriate response rates (necrosis ≥ 90%) was observed in the DEB-TACE group (44.7% vs 32.0%, P = 0.2834). The mean percentage of necrosis in the cumulative tumor area was 58.8% ± 36.6% in the DEB-TACE group and 50.2% ± 38.1% in the c-TACE group (P = 0.4856). Fibrotic and inflammatory reactions surrounding the tumor nodule were markedly more common in the DEB-TACE group (P < 0.0001, for both the parameters). The three-year recurrence-free survival was higher in DEB-TACE-treated patients than in conventionally treated patients (87.4% vs 61.5%, P = 0.0493). Other factors affecting recurrence-free survival included viable tumor beyond Milan Criteria on histopathological examination, the percentage of necrosis on CTA ≤ 50% and a pre-transplant serum α-fetoprotein level greater than 70 ng/mL. On multivariate analysis, the lack of treatment with DEB-TACE, high levels of α-fetoprotein and viable tumor beyond Milan Criteria at histology examination were identified as independent predictors of tumor recurrence. CONCLUSION: DEB-TACE can effectively promote tumor necrosis and improves recurrence-free survival after LT in HCC.

Cancer stem cell gene profile as predictor of relapse in high risk stage II and stage III, radically resected colon cancer patients.

Clinical data indicate that prognostic stratification of radically resected colorectal cancer based on disease stage only may not be always be adequate. Preclinical findings suggest that cancer stem cells may influence the biological behaviour of colorectal cancer independently from stage: objective of the study was to assess whether a panel of stemness markers were correlated with clinical outcome in resected stage II and III colon cancer patients. A panel of 66 markers of stemness were analysed and thus patients were divided into two groups (A and B) with most patients clustering in a manner consistent with different time to relapse by using a statistical algorithm. A total of 62 patients were analysed. Thirty-six (58%) relapsed during the follow-up period (range 1.63-86.5 months). Twelve (19%) and 50 (81%) patients were allocated into group A and B, respectively. A significantly different median relapse-free survival was observed between the 2 groups (22.18 vs 42.85 months, p=0.0296). Among of all genes tested, those with the higher "weight" in determining different prognosis were CD44, ALCAM, DTX2, HSPA9, CCNA2, PDX1, MYST1, COL1A1 and ABCG2. This analysis supports the idea that, other than stage, biological variables, such as expression levels of colon cancer stem cell genes, may be relevant in determining an increased risk of relapse in resected colorectal cancer patients.

Role of ß4 integrin in HER-3-negative, K-RAS wild-type metastatic colorectal tumors receiving cetuximab.

AIMS: Altered α6ß4 integrin expression has been demonstrated in HER-3-negative tumors and may be responsible for anti-HER treatment resistance. The current study aimed to evaluate the interaction between polymorphisms of α6 and ß4 integrins and clinical outcome in HER-3-negative, K-RAS wild-type colorectal cancer patients receiving cetuximab. PATIENTS & METHODS: K-RAS analysis was performed via direct sequencing, HER-3 was evaluated by immunohistochemistry and genotyping of α6 and ß4 integrins was performed by real-time PCR. RESULTS: An univariate analysis, the ß4 rs8669, rs871443 and rs9367 polymorphisms correlated with progression-free and overall survival. On multivariate analysis, only the ß4 rs8669 maintained an independent role in influencing progression-free survival. CONCLUSION: We believe that ß4 rs8669 genotyping may help to identify a subgroup of HER-3-negative, K-RAS wild-type colorectal cancer patients who are more likely to benefit from anti-EGFR treatment. Our findings could also be relevant in planning future trials testing treatment strategies against the integrin-activated molecular pathways.

Primary intra-abdominal synovial sarcoma: a case report.

UNLABELLED: The authors report a case of intra-abdominal synovial-sarcoma of the gastrocolic ligament in a 64-years-old woman hospitalized for a palpable abdominal mass and pain. CT scan detected an intra-abdominal mass extended through the abdominal wall into the soft tissues, causing compression and dislocation of intra-abdominal structures (left liver, gallbladder, pylorus and gastric antrum, duodenal bulb). At its back, it was in contact with the pancreas, the vena cava and the right kidney. Biopsy revealed that the mass was an intra-abdominal synovial-sarcoma. Patient received preoperative chemotherapy. After three chemotherapy cycles the patient was admitted to hospital for anemia. CT-scan revealed mass necrosis and bleeding. After red blood cells transfusions, the patient underwent surgery and the mass was resected. Histopathological study confirmed the diagnosis of biphasic Synovial-Sarcoma. SYT-SSX1/2 fusion molecular assessment was attempted, but it was not possible to evaluate the presence of the t (X, 18) (p11.2; q11.2) traslocation. The patient was discharged in good health and received adjuvant chemotherapy. CT-scan after 18 months showed pulmonary and intra-abdominal relapse of the disease. KEY WORDS: Gastrocolic ligament, Intra-Abdominal synovial-sarcoma.

Primary intra-abdominal synovial sarcoma: a case report.

The authors report a case of intra-abdominal synovial-sarcoma of the gastrocolic ligament in a 64-years-old woman hospitalized for a palpable abdominal mass and pain. CT scan detected an intra-abdominal mass extended through the abdominal wall into the soft tissues, causing compression and dislocation of intra-abdominal structures (left liver, gallbladder, pylorus and gastric antrum, duodenal bulb). At its back, it was in contact with the pancreas, the vena cava and the right kidney. Biopsy revealed that the mass was an intra-abdominal synovial-sarcoma. Patient received preoperative chemotherapy. After three chemotherapy cycles the patient was admitted to hospital for anemia. CT-scan revealed mass necrosis and bleeding. After red blood cells transfusions, the patient underwent surgery and the mass was resected. Histopathological study confirmed the diagnosis of biphasic Synovial-Sarcoma. SYT-SSX1/2 fusion molecular assessment was attempted, but it was not possible to evaluate the presence of the t (X, 18) (p11.2; q11.2) traslocation. The patient was discharged in good health and received adjuvant chemotherapy. CT-scan after 18 months showed pulmonary and intra-abdominal relapse of the disease.

Role of vascular endothelial growth factor (VEGF) and VEGF-R genotyping in guiding the metastatic process in pT4a resected gastric cancer patients.

In radically resected gastric cancer the possibility to predict the site of relapse could be clinically relevant for the selection of post-surgical management. We previously showed that specific tumour integrins genotypes are independently associated with either peritoneal or hematogenous metastases (ITGA and ITGV). Recently VEGF and VEGF-R polymorphisms have been demonstrated to potentially affect tumour angiogenesis and the metastatic process in gastric cancer. We then investigated the role of VEGFs and VEGF-R genotyping in determining either peritoneal carcinosis or hematogenous metastases in radically resected gastric cancer patients. Tumour genotyping for integrins (ITGA and ITGV) was also performed according to our previous findings. Genotyping for VEGF-A, VEGF-C, VEGFR-1,2,3 and ITGA and ITGV was carried out on pT4a radically resected gastric tumours recurring with either peritoneal-only carcinosis or hematogenous metastases. 101 patients fulfilled the inclusion criteria: 57 with peritoneal carcinomatosis only and 44 with hematogenous spread only. At multivariate analysis, intestinal histology and the AC genotype of rs699947 (VEGFA) showed to independently correlate with hematogenous metastases (p = 0.0008 and 0.008 respectively), whereas diffuse histology and the AA genotype of rs2269772 (ITGA) independently correlated with peritoneal-only diffusion (p = <0.0001 and 0.03 respectively). Our results seem to indicate that combining information from genotyping of rs699947 (VEGFA, AC), rs2269772 (ITGA, AA) and tumour histology could allow clinicians to individuate gastric cancer at high risk for recurrence either with peritoneal or hematogenous metastases. The selection tool deriving from this analysis may allow an optimal use of the available treatment strategies in these patients.

Maspin expression is a favorable prognostic factor in non-small cell lung cancer.

OBJECTIVE: To evaluate prognostic impact of maspin expression in patients with resected non-small cell lung cancer (NSCLC). STUDY DESIGN: From 1996 to 2001, 439 patients underwent radical surgery for NSCLC at the Polytechnic University of the Marche Region. Maspin expression was detected as cytoplasmic and nuclear staining of neoplastic cells. For cytoplasmic staining, cases were classified as negative, low positive, and high positive. In positive cases, intensity of staining was also considered and scored. A similar classification was used for nuclear staining, but intensity was not considered. RESULTS: The analysis showed that smoking history, pathologic stage of disease, N status, histologic grading, sex, and Eastern Cooperative Oncology Group performance status had a prognostic impact on overall survival (OS). Expression of maspin was also found to be an independent prognostic factor. A statistically significant longer OS was seen in patients with higher compared with lower expression of nuclear maspin, and poorer OS was present in patients with a higher intensity of cytoplasmic staining. Nuclear expression of maspin was also found to be an independent prognostic factor at multivariate analysis. CONCLUSION: Results suggest that overexpression of maspin correlates with favorable prognosis in NSCLC. and may be a useful clinical marker.

Phosphorylated AKT and MAPK expression in primary tumours and in corresponding metastases and clinical outcome in colorectal cancer patients receiving irinotecan-cetuximab.

BACKGROUND: Clinical observations suggested that a non negligible proportion of patients, ranging from 40% to 70%, does not seem to benefit from the use of anti-EGFR targeted antibodies even in the absence of a mutation of the K- RAS gene. The EGFR pathway activation via the Ras-Raf-MAP-kinase and the protein-serine/threonine kinase AKT could determine resistance to anti-EGFR treatment. METHODS: We tested the interaction between phosphorylated AKT and MAPK expression in colorectal tumours and corresponding metastases and global outcome in K-RAS wild type patients receiving irinotecan-cetuximab. RESULTS: Seventy-two patients with histologically proven metastatic colorectal cancer, treated with Irinotecan and Cetuximab based chemotherapy, were eligible for our analysis.In metastases pAKT correlated with RR (9% vs. 58%, p = 0.004), PFS (2.3 months vs. 9.2 months p < 0.0001) and OS (6.1 months vs. 26.7 months p < 0.0001) and pMAPK correlated with RR (10% vs. 47%, p = 0.002), PFS (2.3 months vs. 8.6 months p < 0.0001) and OS (7.8 months vs. 26 months p = 0.0004). At multivariate analysis pAKT and pMAPK in metastases were able to independently predict PFS. pAKT in metastases independently correlated with RR as well DISCUSSION: pAKT and pMAPK expression in metastases may modulate the activity of EGFR-targeted antibodies. We could speculate that in patients with pAKT and pMAPK metastases expression targeting these factors may be crucial.

Nuclear factor-κB predicts outcome in locally advanced rectal cancer patients receiving neoadjuvant radio-chemotherapy.

BACKGROUND: NF-κB expression has been shown to be responsible for resistance to antineoplastic agents. AIMS: The aim of our study was to investigate the importance of NF-κB expression as prognostic factor in locally advanced rectal cancer patients receiving neoadjuvant radiochemotherapy. METHODS: We retrospectively analysed the immunoreactivity for NF-κB in patients with locally advanced rectal cancer who underwent neoadjuvant treatment (chemotherapy and/or radiotherapy) in our Institution between March 2003 and June 2006. RESULTS: Seventy-four consecutive patients were enrolled into this study. Immunohistochemistry analysis for NF-κB was performed both in biopsies and in primary tumour samples. NF-κB was considered positive when at least 1% of the tumour cells showed nuclear positivity. A significant correlation between a positive NF-κB nuclear expression, both in biopsies and in tumour samples, and a worse overall survival was observed. Moreover, median time to progression was significantly shorter in the NF-κB-positive subgroup of patients. CONCLUSION: Globally, our findings seem to suggest that NF-κB could represent an important parameter able to predict the outcome in patients receiving neoadjuvant treatment for rectal cancer. It also could be useful in order to select patients to receive adjuvant chemotherapy, intensifying the adjuvant therapy and, in the next future, obviating the use of drugs involving NF-κB system in their mechanism of action in NF-κB-positive patients.

Natural history of imatinib-naive GISTs: a retrospective analysis of 929 cases with long-term follow-up and development of a survival nomogram based on mitotic index and size as continuous variables.

Gastrointestinal stromal tumor (GIST) natural history per se has not been extensively investigated yet, with most data being drawn from large studies with a relevant referral bias. Hence, the estimation of prognosis still remains a critical issue. We retrospectively evaluated 929 GISTs resected between 1980 and 2000 in 35 Italian institutions. A total of 526 patients were found to be suitable for refining risk assessment through the development of a survival nomogram. Median follow-up was 126 months. On testing for potential prognostic parameters, age, tumor site, size, and mitotic index proved to be predictors of OS on both univariable and multivariable Cox model analyses, whereas necrosis and cytonuclear atypia were significant on univariable analysis only. The discriminative ability of the model, including the parameters selected after a backward procedure (C=0.72), improved compared with the National Institutes of Health 2002 (C=0.64) and the National Comprehensive Cancer Network 2007 (C=0.63). On the basis of these data we developed a prognostic nomogram for survival that considers site, size, and mitotic index as continuous variables, providing estimates stratified for patients aged ≤65 and >65 years. This nomogram is a tool based on survival. It overcomes problems that result from artificial categorization of continuous variables. We believe that in the future this should also be attempted by nomograms based on the risk of relapse.

Gastrointestinal stromal tumors: the histology report.

Gastrointestinal stromal tumors (GISTs) represent a mesenchymal neoplasm occurring primarily in the gastrointestinal tract, and showing differentiation toward the interstitial cell of Cajal. Its incidence is approximately 15 case/100,000/year. Stomach and small bowel are the most frequently affected anatomic sites. GIST represents a morphological, immunophenotypical and molecular distinct entity, the recognition of which has profound therapeutic implications. In fact, they have shown an exquisite sensitivity to treatment with the tyrosine kinase inhibitor imatinib. Diagnosis relies upon morphology along with immunodetection of KIT and/or DOG1. When dealing with KIT negative cases, molecular analysis of KIT/PDGFRA genes may help in confirming diagnosis. Molecular evaluation of both genes are in any case recommended as mutational status provides key predictive information. Pathologists also play a key role in providing an estimation of the risk of biological aggressiveness, which is currently based on anatomic location of the tumor, size, and mitotic activity.

Coeliac disease in Libyan children: a screening study based on the rapid determination of anti-transglutaminase antibodies.

BACKGROUND: Coeliac disease is a common disorder in North Africa; however, there are no data on coeliac disease prevalence in Libya. AIM: (1) To determine coeliac disease prevalence in Libyan schoolchildren by screening with a rapid test for IgA anti-transglutaminase determination on a blood drop; (2) to evaluate the accuracy of the rapid anti-transglutaminase test. PATIENTS AND METHODS: We screened 2920 students (1452 females and 1468 males) attending school in El Beida (Libya) by the rapid anti-transglutaminase test. Conventional ELISA anti-transglutaminase in rapid test positives and small intestinal biopsy in ELISA positives were performed for coeliac disease diagnosis. Conventional IgA anti-transglutaminase was performed also in 800 rapid test negative subjects. RESULTS: The rapid anti-transglutaminase test was positive in 50/2920 (1.7%) subjects but only 20/50 were confirmed by the ELISA determination. The diagnosis of coeliac disease was biopsy-confirmed in 19 out of these 20. The serum ELISA IgA anti-transglutaminase was positive in 4 out of 800 rapid test negative children. Coeliac disease prevalence was 0.79-1.13%. CONCLUSIONS: Coeliac disease in Libyan children is as common as in Europe, affecting around 1% of the general population. The rapid test for IgA anti-transglutaminase determination on a blood drop was not an efficient screening test.

The role of HER-3 expression in the prediction of clinical outcome for advanced colorectal cancer patients receiving irinotecan and cetuximab.

Preclinical data suggested that, in the presence of human epidermal growth factor receptor (HER)-3-altered activation, colorectal cancer cells may escape anti-epidermal growth factor receptor (EGFR)-mediated cell death. HER-3 overexpression may then represent a key factor for resistance to anti-EGFR antibodies in colorectal cancer. The aim of our analysis was to investigate a possible correlation between HER-3 expression and clinical outcome in wild-type K-RAS advanced colorectal cancer patients receiving cetuximab and irinotecan. We retrospectively analyzed immunoreactivity for HER-3 in wild-type K-RAS advanced colorectal cancer patients receiving irinotecan and cetuximab. Eighty-four advanced wild-type K-RAS colorectal cancer patients were available for HER-3 analysis. Forty patients (48%) had a HER-3(-) colorectal tumor, whereas the remaining 44 cases (52%) were deemed HER-3(+). In patients with HER-3(-) and HER-3(+) tumors, we observed a partial response in 17 (42%) and eight (18%) patients respectively; progressive disease occurred in 11 (35%) and 26 (53%) patients with HER-3(-) and HER-3(+) tumors, respectively (p = .003). The median progression-free survival time was 6.3 months in patients with HER-3(-) tumors and 2.8 months for those who had HER-3-overexpressing tumors (p < .0001). The median overall survival time was 13.6 months in patients showing HER-3(-) tumors and 10.5 months for those who had HER-3-expressing tumors (p = .01). HER-3 proved to be a predictive factor for clinical outcome in wild-type K-RAS colorectal cancer patients treated with cetuximab. Combined HER-3 and K-RAS analysis may represent an effective strategy for better selection of responding colorectal cancer patients.

Molecular and clinicopathologic characterization of gastrointestinal stromal tumors (GISTs) of small size.

Although Gastrointestinal stromal tumors (GISTs) affect about 0.0014% of the population, GISTs smaller than 1 cm (microGISTs) are detectable in about 20% to 30% of elderly individuals. This suggests that microGISTs likely represent premalignant precursors that evolve only in a minute fraction of cases toward overt GISTs. We sought histopathologic and molecular explanations for the infrequent clinical progression in small GISTs. To investigate the mechanisms of GIST progression and identify subsets with differential malignant potential, we carried out a thorough characterization of 170 GISTs <2 cm and compared their KIT/PDGFRA status with overt GISTs. The proliferation was lower in microGISTs compared with GISTs from 1 to 2 cm (milliGISTs). In addition, microGISTs were more frequently incidental, gastric, spindle, showed an infiltrative growth pattern, a lower degree of cellularity, and abundant sclerosis. The progression was limited to 1 ileal and 1 rectal milliGISTs. KIT/PDGFRA mutations were detected in 74% of the cases. The overall frequency of KIT/PDGFRA mutation and, particularly, the frequency of KIT exon 11 mutations was significantly lower in small GISTs compared with overt GISTs. Five novel mutations, 3 in KIT (p.Phe506Leu, p.Ser692Leu, p.Glu695Lys) 2 in PDGFRA (p.Ser847X, p.Ser667Pro), plus 4 double mutations were identified. Small GISTs share with overt GIST KIT/PDGFRA mutation. Nevertheless, microGISTs display an overall lower frequency of mutations, particularly canonical KIT mutations, and also carry rare and novel mutations. These molecular features, together with the peculiar pathologic characteristics, suggest that the proliferation of these lesions is likely sustained by weakly pathogenic molecular events, supporting the epidemiologic evidence that microGISTs are self-limiting lesions.