samples into at least two groups with different prob- abilities of developing metastatic disease. Although the gene sets were derived using biochemical pathways, we did not observe simple differences in biochemical pathways between the groups; possibly with a larger sample set, more detailed biochemical differences will become evident. Our data suggest that appreciation of these GIST subsets with distinct clinical behavior could be used to stratify GIST patients in clinical trials and in patient management. Miettinen risk group classifica- tion also identified distinct risk groups in our 60 GIST cases. In particular, our analysis also identified subsets of Miettinen high- and intermediate-risk samples that different in the risk of metastasis. When the high- and intermediate-risk GIST samples were examined with- out the low- and very low-risk samples, the individual AF-gene set, OVCA-gene set, RCC-gene set, and the combined gene set were associated with the time to development of metastasis. This finding suggests that further characterization of recurrence risk among sam- ples classified as high- or intermediate-risk is possible. Furthermore, these results validate the potential role of the use of these gene sets in predicting the behavior of heterogeneous tumor sets.
Both the current and CINSARC gene sets identified subsets of the UPS samples, when analyzed as a separate group, that differed in time to metastasis. Interestingly, the current study also detected subsets of LipoD, when analyzed as a separate group, that differed in probability of metastasis, but did not detect such subsets in the LMS or OTH subgroups. These differences were apparent even after excluding grade 1 tumors from the analysis. In con- trast, the CINSARC gene set identified subsets of LMS, when analyzed as a separate group, that differed in prob- ability of metastasis, but did not detect such subsets in the LipoD subgroup . Copy number losses, which may also reflect genomic instability, have recently been shown to identify subgroups of LipoD with a poor prognosis . These results are consistent with the hypothesis that geneexpression patterns that correlate with metastatic propen- sity may depend on the background geneexpression of the tumor, which may be determined by other gene sets and partly reflected by histology. For example, a set of genes that predicts metastasis in LMS might not be pre- dictive in UPS, or a gene might be predictive in lung can- cer but not colon cancer.
GISTs are a rare special mesenchymal tumor group, making up less than 1% of primary tumors of the gas- trointestinal system . Their biological behavior is hard to predict . Many macroscopic and microscopic para- metres have been suggested to identify the prognosis, including tumor localization and diameter, invasion of peripheral tissue, growth pattern, mucosal invasion, pre- dominant tumor cell type, cellularity, nuclear pleo- morphism, mitotic count, Ki67 proliferative activity index, p53 gene mutation, histological grade, DNA ana- lysis, margins of surgical operation, necrosis and immu- nophenotyping [1-7]. Even though efforts continue for Table 2 Clinicopathological characteristics of GIST
Abstract: We have previously described immune cells in untreated primary gastrointestinalstromaltumors (GIST). Here we compare immune cells in metastatic and primary GIST, and describe their chemoattractants. For this pur- pose, tissue microarrays from 196 patients, 188 primary and 51 metastasized GIST were constructed for paraffin staining. Quantitative analysis was performed for cells of macrophage lineage (Ki-M1P, CD68), T-cells (CD3, CD56) and B-cells (CD20). Chemokine gene-expression was evaluated by real-time RT-PCR. Immuno-localisation was veri- fied by immunofluorescence. Ki-M1P+ cells were the predominant immune cells in both primary and metastatic GIST (2 8.8% ± 7.1, vs. 26.7% ± 6.3). CD68+ macrophages were significantly fewer, with no significant difference be- tween primary GIST (3.6% ± 2.1) and metastases (4.6% ± 1.5). CD3+ T-cells were the most dominant lymphocytes with a significant increase in metastases (7.3% ± 2.3 vs. 2.2% ± 1.8 in primary GIST, P < 0.01). The percentage of CD56+ NK-cells was 1.1% ± 0.9 in the primary, and 2.4 ± 0.7 (P < 0.05) in the metastases. The number of CD20+ B-cells was generally low with 0.6% ± 0.7 in the primary and 1.8% ± 0.3 (P < 0.05) in the metastases. Analysis of the metastases showed significantly more Ki-M1P+ cells in peritoneal metastases (31.8% ± 7.4 vs. 18.2% ± 3.7, P < 0.01), whilst CD3+ T-cells were more common in liver metastases (11.7% ± 1.8 vs. 4.4% ± 2.6, P < 0.01). The high- est transcript expression was seen for monocyte chemotactic protein 1 (MCP1/CCL2), macrophage inflammatory protein 1α (MIP-1α/CCL3) and the pro-angiogenic growth-related oncoprotein 1 (Gro-α/CXCL-1). Whilst the ligands were predominantly expressed in tumor cells, their receptors were mostly present in immune cells. This locally spe- cific microenvironment might influence neoplastic progression of GIST at the different metastatic sites.
are the most important prognostic indicators of GISTs. However, they do not always reliably pre- dict patient outcomes. The clinical behavior of GIST varies, and some small and mitotically inactive GISTs show aggressive behaviors . A reliable method to predict the prognosis of GIST is necessary for clinical management. Alteration of cell-cycle regulatory proteins has been implicated in the pathogenesis and tumor progression of various kinds of human cancers. Loss of p16 expression has been reported to be associated with progression to malignant disease . However, p16 overexpression was found in some tumors, and it was associated with the aggressiveness of disease subtypes [6-8]. Although there have been extensive stud- ies of p16 expression in GISTs, discrepancies still exist with respect to its prognostic value . Loss of p16 expression has been previ- ously reported as a negative prognostic factor in GISTs. Schneider-Stock et al.  did not find any correlation between p16 gene alteration and clinicopathologic variables, but p16 loss was associated with a poor prognosis and p16 expression was higher in the benign GISTs. Huang et al.  also demonstrated that com- plete loss of p16 expression preferentially affected intermediate- and high-risk groups, and they suggested that p16 deregulation might be involved in early tumorigenesis. Several other studies have confirmed this cor- relation and its implication for poor prognosis [21-23]. However, Haller et al.  demonstrat- ed that loss of chromosomal region 9p21 led to reduced mRNA and p16 expression in GISTs. Steigen et al.  also showed that patients with p16-expressing GISTs had a significantly worse OS than those without p16 expression. In addition, p16-expressing GISTs tended to have a larger size and a higher mitotic count (> 5/50 HPF) compared with those not expressing Table 2. Univariate and multivariate analyses of clinicopathologic factors affecting the survival of patients with gastrointestinalstromaltumors
The recent advances in immunohistochistry and molecular aspects increased the rate of accurate diagnosis. Imatinib is the standard first line systemic therapy for metastatic cases. Neoadjuvant treatment has been used for locally advanced tumors. Surgical resection is the primary modality for early, localized cases. Post-operatively, those who have high risk profiling will be candidates for adjuvant Imatinib.
fluorodeoxyglucose (FDG) tracer with excess avidity. The reported sensitivity of PET for GIST is 86 to 100% [24,25]. PET can be useful for detecting an unknown pri- mary site or resolving ambiguities from CT . On upper GI endoscopy, a smooth, mucosa-lined protrusion of the bowel wall, with or without signs of bleeding and ulceration may be seen . However, endoscopic biop- sies using standard techniques usually do not obtain suf- ficient tissue for a definite diagnosis . Endoscopic ultrasound (EUS) -guided fine-needle biopsy forceps also may not yield enough tissue, but might exclude other lesions that arise sub-mucosally. Snare biopsies can re- sult in perforation and generally should be avoided ex- cept in carefully selected cases . A preoperative biopsy is not generally recommended for a resectable le- sion in which there is a high suspicion for GIST, and the patient is otherwise operable. However, a biopsy should be done to confirm the diagnosis particularly when metastatic disease is present or suspected. If preopera- tive imatinib is considered in a patient who has a large locally advanced lesion thought to represent GIST, a bi- opsy should be done. An EUS-guided biopsy (in carefully selected patients and preferably of the primary lesions) is more desirable than a percutaneous biopsy .
GISTs are the most common soft tissue sarcoma of the gastrointestinal tract, resulting most commonly from KIT or platelet-derived growth factor receptor alpha (PDGFRalpha)- activating mutations [19–21]. However, they have distinct genetic background and geneexpression patterns according to localization, genotype and aggressiveness [22, 23]. Chr5p15.33 harbors a unique cancer susceptibility region that contains at least two plausible candidate genes: TERT and CLTPM1L [24–27]. The TERT gene has been mapped to chromosome 5p15.33 and consisted of 16 exons and 15 introns spanning 35kb of genomic DNA . It encodes the catalytic subunit of the telomerase reverse transcriptase, which, in combination with an RNA template (TERC), adds nucleotide repeats to chromosome ends [29, 30]. The CLTPM1L gene, also known as cisplatin resistance-related protein 9 (CRR9p), encodes a protein that is overexpressed in lung and pancreatic cancer, promotes growth and survival, and is required for KRAS driven lung cancer [31, 32]. It confer resistance to apoptosis caused by genotoxic agents in association with up-regulation of the anti-apoptotic protein, Bcl-xL . Studies indicate that the TERT-CLPTM1L region may harbor multiple elements that have the capacity to influence molecular phenotypes in cancer development [16, 34]. Thus, It is possible to study that the interplay between risk variants, multiple biological mechanisms and attributed genes, influence various cancers, including GISTs.
In total, 175 GIST cases, diagnosed and treated between January 2005 and January 2011, were retrieved from the hospitalization archives of the clinical medical college of Yangzhou University/Northern Jiangsu People’s Hospital (NJPH), Yangzhou, China. Of these patients, 133 received surgical resection. The inclusion criteria for this study were: (1) primary localized GISTs with R0 resection; (2) no other synchronous primary tumors; and (3) preoperative or post- operative adjuvant treatment (chemotherapy, radiotherapy and IM) were not given. Of these, 49 patients were ex- cluded owing to: non-R0 resection (n = 7), receiving adju- vant treatment (n = 15), having other synchronous tumors (n = 13), missing clinical data (n = 8) or inadequate material for histological examination (n = 6). Thus, 84 GIST patients with full clinicopathological records and adequate formalin- fixed paraffin-embedded (FFPE) tissue blocks were enrolled in the current study. The FFPE tumor specimens were obtained from the archives of the Department of Pathology at NJPH.
Laparoscopic treatment is reported to confer decreased recurrence rates, shorter hospital stays, and a lower mor- bidity. This treatment strategy may be indicated in certain anatomic locations including the anterior wall of the stomach, jejunum, and ileum . Typically GISTs do not invade adjacent organs and as such the tumor can be lifted away, making laparoscopic surgery a viable preferred modality . The reported success rates are excel- lent, from 92% - 96% . There are, however, concerns about the oncologic safety and technical feasibility of laparoscopic resection, predominately related to tumor size, risk of tumor rupture, and adequacy of the resection margins. The National Comprehensive Cancer Network Clinical Practice Guidelines for Optimal Management of Patients with GIST states that a laparoscopic approach should be reserved for tumors <2 cm. However, stu- dies report this technique being used for tumors 2.7 - 6.0 cm with low recurrence rates and margin negativity suggests that a large tumor size should not be an absolute contraindication to laparoscopic resection . For GISTs > 5 cm, the use of an endobag may be used to protect the exophytic lesion from lacerations . Spe- cially designed techniques such as a “non-touch lesion-lifting” method have been described in the treatment of GISTs .
In one patient with malignant ileal GIST, the tumor was fixed at the root of the mesentery and was infiltrating the pelvic organs, vessels and right ureter, and also had secondaries in the liver. It was locally inoperable and finally the abdomen had to be closed after taking a biopsy. Cut section of the tumors showed grey-white areas and three out of twelve cases also showed focal areas of haemorrhage and necrosis. Microscopic examination revealed spindle cells with elongated hyperchromatic nucleus and moderate eosinophilic cytoplasm arranged in short fascicles along with areas of tumor cells
Studies on GISTs in young patients are limited due to their rarity, and none have been conducted in Asian populations. GISTs from patients under the age of 30 years were retrospectively reviewed and were analyzed for clinicopathologic features, immunohistochemistry and mutations for exon 9, 11, 13, and 17 of KIT gene and exon 12, 14, and 18 of PDGFRA gene. Two pediatric (<18-years old) and 20 young adult (18- to 30-years old) cases of GIST were found. Of the 20 GISTs in young adults, 12 (60%) were from extra-gastric locations (six duodenum, five jejunum, and one esophagus), and 16 (80%) showed a spindle cell morphology. Mutations of KIT or PDGFRA genes were identified in 14 (78%) of the 18 cases. Com- pared with cases of pediatric GIST, cases of young adults with GIST are heterogeneous and share the characteristics of both GISTS in pediatric and adult cases .
Of the 226 GISTs, only one case (0.44%) exhib- ited a loss of BAP1 expression (Figure 1A). All other cases exhibited diffuse homogeneous BAP1 positivity (Figure 1B). We next stained a whole section from a representative tumor block to confirm the loss of BAP1 expression, and observed that the tumor cells were com- pletely negative for BAP1. Statistically, we ob- served no significance associations between loss of BAP1 expression and clinicopathologic factors. In univariate analysis, small intestinal and colorectal GISTs, GISTs with necrosis, re- currence/metastasis, or a higher risk of malig- nancy were significantly associated with a poor OS and DFS. In a multivariate analysis, GISTs with a higher risk of malignancy and recur- rence/metastasis were confirmed as indepen- dent prognostic factors (Tables 2, 3).
The identification of a family that exhibited an autosomal dominant inheritance pattern of GIST further confirmed the oncogenic potential of mutant, uncontrollably active KIT in the pathogenesis of GIST in humans. They harbored a germline activating KIT mutation, similar to the mutations that were seen in sporadic cases of GIST on genetic analysis.  Often, these tumors may not present clinically until the second or third decade of life, and some even present in far advanced age. KIT mutations have also been documented in very small (less than 1 cm) GISTs that were detected incidentally and that appear morphologically benign. These findings support the hypothesis that activating mutations in the KIT protooncogene represent an early transforming mechanism in GIST oncogenesis. However, since many tumors harboring this mutation can remain small for years, there must be other key signaling steps that confer an aggressive and malignant phenotype to GIST cells. These other molecular pathways remain poorly understood. Unique elements of the downstream signaling cascades in GIST are being actively elucidated, and these appear to differ from KIT signaling in hematologic neoplasia in that the STAT5 pathway is not typically activated in GIST, whereas STAT1 and STAT3 are activated at a high level.
Therefore, TCB and FNA are not recommended if the patient is not being considered for conversion therapy, or if the clini- cian needs to differentiate GISTs from other tumors, for the following reasons: 1) stromaltumors are generally relatively easy to remove, 2) tumor rupture should be prevented in case of implantation metastasis, and 3) because of the presence of tumor capsule, it is difficult to get sufficient tissue to make a definite diagnosis using these modalities. 23 An MRI is useful
Metastasis is an indicator of poor prognosis for any can- cer patient, but the issue is even more difficult if the primary tumor is unknown and the diagnosis has to be made solely based on the discovery of metastases. This ‘ type ’ of cancer is known as a cancer of unknown pri- mary (CUP) and represents a condition requiring speci- fic clinical attention. The origin of the metastasis needs to be identified as primary treatment regimes for cancer are typically based on the anatomical origin and histolo- gical type of the primary tumor. Studies by several groups [4-7,20] have shown that finding the tissue of origin of metastatic samples is possible based on geneexpression data. Some of these tests are already com- mercially available and have been clinically applied [13-15,17]. Most of the previously described approaches are based on a fixed set of genes measured with a cus- tom designed array, multiplexed PCR or other molecular profiling assay. We sought to explore an approach where one can algorithmically solve the tissue of origin of the sample by comparing the whole genome expres- sion profile of the sample to a large collection of refer- ence data from the public domain, extracted from the GeneSapiens database . This approach has the advantage of improving constantly as more data are acquired and as algorithms are optimized. This also allows more flexible customization of the molecular pro- filing to determine things such as where the metastasis originates from or whether the metastasis originates, for example, from esophagus or lung.
The demographic and clinicopathologic data of our patients are summarized in Table 1. Five women and two men, with a median age of 69 years (range, 39–81) were diagnosed with a schwannoma of the GI tract. The tumor was localized to the stomach in four patients (n = 4) and in the small intestine in three patients (n = 3), with a median tumor size of 29 mm (range, 12–70). Out of the four gastric schwannomas, two were localized in the gastric body and two in the antrum. Symptoms were reported in only one patient with gastric schwannoma who complained of persistent epigastric pain and nausea. In six cases the tumor was an incidental finding during imaging, endoscopic or surgical procedures for other reason. Particularly the tumors were incidentally discov- ered during surgery for colon carcinoma (case Nr. 1) and diverticulitis of sigmoid (case Nr. 3, 4), during an abdom- inal ultrasound as preventative measure (case Nr. 2) and during a upper GI gastroscopy performed as preventative measure as well (case Nr. 5). Furthermore, in the seventh patient, the tumor was an incidental finding on a thoracic CT scan performed for evaluation of hemoptysis. CT scan
There is also an association between regorafenib therapy and an increased incidence of myocardial ischemia, poten- tially linked to the inhibition of VEGF pertaining to its role in cardiovascular function. Patients with preexisting cardio- vascular comorbidities, including venous thrombus, embolic events such as stroke or transient ischemic attacks, pulmonary embolus, cardiac arrhythmias requiring antiarrhythmic therapy, uncontrolled hypertension despite optical medical management, or severe heart failure within 6 months before the start of treatment were excluded from the trial. Although a Phase I trial assessing the cardiovascular safety of regorafenib in solid tumors showed the drug to have modest effects on QT/QTc and left ventricular ejection fraction. 55 In 72% of
Surgical resection of the tumor is the current priority management for localized GISTs . Owing to GISTs have a risk of tumor rupture dur- ing operation which may lead to the spread of tumor cells, en bloc resection of the tumor is of importance. In recent years, with the develop- ment of minimally invasive techniques, the util- ity of laparoscopic wedge resection (LWR) for gastric GISTs has been well established and increasingly emerged as the preferred treat- ment option. And even gastric GISTs larger than 5 cm were also be resected by LWR . Since GISTs seldom spread via the lymphatic system, it is generally accepted that lymph node dissec- tion is not necessary . For patients with unresectable tumors or advanced GIST, tyro- sine kinase inhibitors are the suggested treat- ment. Abou Al-Shaar et al.  reported an adre- nal GIST patient with almost complete re- solution of the tumor metabolism after receiv- ing a 3-month anti-tyrosine kinase therapy (imatinib). In addition, as GISTs are generally resistant to radiotherapy and chemotherapy, these treatments are seldom used in clinical practice .
III trial of adjuvant imatinib in patients with GIST at least 3 cm in diameter was done (American College of Surgeons Oncology Group Adjuvant Trial Z9001). The trial was not blinded, and an interim analysis has shown that patients receiving treatment had a statistically significant increase in recurrence-free survival. Seven hundred and thirteen patients having a histologic diagnosis of KIT-positive GIST, tumor size $3 cm, and complete gross resection within 14 to 70 days prior to registration were enrolled in this study. Patients were randomized to receive imatinib at a dose of 400 mg/day or placebo for one year. The primary endpoint of this study was recurrence-free survival. At the end of the 1-year treatment period, an estimated 98% of patients in the treatment group achieved recurrence-free survival at 1 year, compared with 82% of patients in the placebo group. This yielded a 16% absolute risk reduction, and the difference in recurrence-free survival between the two groups was statisti- cally significant (P = 0001). This difference was observed as early as 6 months, and was even more pronounced in patients with tumors larger than 10 cm. Based on the results of this trial, the US Food and Drug Administration (FDA) approved the use of imatinib at a dose of 400 mg/daily in the adjuvant setting of patients with GIST larger than 3 cm. 31 The optimal