Prognostic value of KIT/PDGFRA mutations in gastrointestinal stromal tumors: a meta-analysis

Establishing biomarkers for soft tissue sarcomas

INTRODUCTION

Soft tissue sarcomas (STS) are a rare and diverse group of tumors. Curative options are limited to localized disease, with surgery being the mainstay. Advanced stages are associated with a poor prognosis. Currently, the prognosis of the patient is based on histological classification and clinical characteristics, with only a few biomarkers having entered clinical practice.

AREAS COVERED

This article covers extensive recent research that has established novel potential biomarkers based on genomics, proteomics, and clinical characteristics. Validating and incorporating these biomarkers into clinical practice can improve prognosis, prediction of recurrence, and treatment response. Relevant literature was collected from PubMed, Scopus, and clinicaltrials.gov databases (November 2023).

EXPERT OPINION

Currently, defining prognostic markers in soft tissue sarcomas remains challenging. More studies are required, especially to personalize treatment through advanced genetic profiling and analysis using individual tumor and patient characteristics.

Prognostic analysis of 2-5 cm diameter gastric stromal tumors with exogenous or endogenous growth

BACKGROUND

There has been limited research on the prognosis differences in patients with gastric stromal tumor invasion of the plasma membrane surface. This study intended to investigate whether there is a difference in prognosis in patients with endogenous or exogenous 2-5 cm diameter GISTs.

METHODS

We retrospectively analyzed the clinicopathological and follow-up data of gastric stromal tumor patients, all of whom underwent surgical resection for primary GIST at Nanjing Drum Tower Hospital from December 2010 to February 2022. We classified patients based on tumor growth patterns and then investigated the association between tumor growth patterns and clinical outcomes. Progression-free survival (PFS) and overall survival (OS) were calculated by the Kaplan‒Meier method.

RESULTS

A total of 496 gastric stromal tumor patients were enrolled in this study, among which 276 patients had tumors of 2-5 cm in diameter. Of these 276 patients, 193 had exogenous tumors, and 83 had endogenous tumors. Tumor growth patterns were significantly related to age, rupture status, resection style, tumor site, tumor size, and intraoperative bleeding. According to Kaplan‒Meier curve analysis, the tumor growth pattern among patients with 2-5 cm diameter tumors was significantly correlated with worse progression-free survival (PFS). Ultimately, multivariate analyses identified the Ki-67 index (P = 0.008), surgical history (P = 0.031), and resection style (P = 0.045) as independent prognostic markers for PFS.

CONCLUSIONS

Although gastric stromal tumors with a diameter of 2-5 cm are classified as low risk, the prognosis is lower for exogenous tumors than for endogenous tumors, and exogenous gastric stromal tumors have a risk of recurrence. Consequently, clinicians should be vigilant regarding the prognosis of patients with this type of tumor.

Prognostic factors of primary gastrointestinal stromal tumors: a cohort study based on high-volume centers

Objective

We aimed to evaluate the clinicopathologic characteristics, immunohistochemical expression and prognostic factors of patients with primary gastrointestinal stromal tumors (GISTs).

Methods

Data from 2,570 consecutive GIST patients from four medical centers in China (January 2001-December 2015) were reviewed. Survival curves were constructed by the Kaplan-Meier method, and Cox regression models were used to identify independent prognostic factors.

Results

Of the included patients, 1,375 (53.5%) were male, and the patient age range was 18 to 95 (median, 58) years. The tumors were mostly found in the stomach (64.5%), small intestine (25.1%) and colorectal region (5.1%). At the time of diagnosis, the median tumor size was 4.0 (range: 0.1-55.0) cm, and the median mitotic index per 50 high power fields (HPFs) was 3 (range: 0-254). Of the 2,168 resected patients, 2,009 (92.7%) received curative resection. According to the modified National Institutes of Health (NIH) classification, 21.9%, 28.9%, 14.1% and 35.1% were very low-, low-, intermediate- and high-risk tumors, respectively. The rate of positivity was 96.4% for c-Kit, 87.1% for CD34, 96.9% for delay of germination 1 (DOG-1), 8.0% for S-100, 31.0% for smooth muscle actin (SMA) and 5.1% for desmin. However, the prognostic value of each was limited. Multivariate analysis showed that age, tumor size, mitotic index, tumor site, occurrence of curative resection and postoperative imatinib were independent prognostic factors. Furthermore, we found that high-risk patients benefited significantly from postoperative imatinib (P<0.001), whereas intermediate-risk patients did not (P=0.954).

Conclusions

Age, tumor size, mitotic index, tumor site, occurrence of curative resection and postoperative imatinib were independent prognostic factors in patients with GISTs. Moreover, determining whether intermediate-risk patients can benefit from adjuvant imatinib would be of considerable interest in future studies.

Ki67 is a biological marker of malignant risk of gastrointestinal stromal tumors: A systematic review and meta-analysis

BACKGROUND

Ki67 is a good marker of cell proliferation in a variety of tumors. High ki67 levels are usually associated with poor prognosis. However, the relationship between Ki67 expression and the risk of malignancy of gastrointestinal stromal tumors (GISTs) is still poorly defined. The current meta-analysis was initiated to address this issue.

METHODS

Studies reporting Ki67 expression and the risk of malignancy in GIST were found by searching Cochrane Library, PubMed, Medline, and Embase until October 31, 2016. A total of 9 studies involving 982 patients were included. Pooled odds ratio (OR) estimates and 95% confidence intervals (CIs) were calculated using a fixed-effect model.

RESULTS

Meta-analysis showed no significant difference in the incidence of Ki67 overexpression between the very low NIH group and the low NIH group (OR: 0.66, 95% CI: 0.25-1.76; P = .41, Pheterogeneity = .25). However, the incidence of Ki67 overexpression gradually increased from the low NIH group to the high NIH group (OR: 0.46, 95% CI: 0.27-0.80; P = .005, Pheterogeneity = .13) and (OR: 0.22, 95% CI: 0.15-0.34; P < .00001, Pheterogeneity = .33).

CONCLUSIONS

There were more GIST patients with Ki67 overexpression in the intermediate and high NIH groups than in the low NIH group. Ki67 overexpression may be a useful marker of the risk of malignant GIST transformation.

Clinicopathological and Prognostic Analysis of Primary Gastrointestinal Stromal Tumor Presenting with Gastrointestinal Bleeding: a 10-Year Retrospective Study

OBJECTIVES

The objectives of this paper were to investigate the clinicopathological characteristics and prognostic factors of GI-bleeding GIST patients and explore whether GI bleeding is a risk factor for GIST relapse.

METHODS

Primary GIST patients with initial symptoms of GI bleeding or no GI bleeding were retrospectively studied.

RESULTS

Up to 178 GI-bleeding GIST patients including 108 (60.7%) males and 70 (39.3%) females were evaluated for the clinicopathological characteristics. The stomach, small bowel, and colorectum were the tumor sites in 82 (46.1%), 85 (47.8%), and 11 (6.2%) patients. Of the 178 patients, 163 GI-bleeding patients had follow-up while another 363 patients from the total population presented without GI bleeding were followed up. Up to 526 patients who received postoperative follow-up were included in the survival analysis. Compared with the 363 non-GI-bleeding patients, GI-bleeding patients developed smaller tumors (P = 0.015) and had a longer relapse-free survival (RFS; P = 0.014). For the 163 GI-bleeding patients, a Cox regression analysis showed that the mitotic count and the platelet-lymphocyte ratio before surgery were independent prognostic predictors for poor outcome regarding RFS. For all 526 patients, a Cox regression analysis indicated that tumor location, mitotic index, platelet-lymphocyte ratio, and GI bleeding were independent prognosis predictors.

CONCLUSION

Compared to non-GI-bleeding GIST patients, patients with GI bleeding were more likely to be male and to have more small intestine GISTs, smaller tumors, and a longer RFS. For GI-bleeding patients, mitotic count and platelet-lymphocyte ratio were independent prognostic indicators. GI bleeding served as a surrogate for smaller GIST and was a protective factor for GIST recurrence.

PDGFRA and KIT Mutation Status and Its Association With Clinicopathological Properties, Including DOG1

Most of the gastrointestinal stromal tumors (GISTs) have gain-of-function mutations in the KIT gene, which can be used as a prognostic marker for the biological behavior of tumors, predictive marker for the response of tyrosine kinase inhibitors, and diagnostic marker. Researchers have focused on PDGFRA mutations because of both their prognostic and predictive potential and DOG1 positivity for diagnosis on GISTs. The aim of this study is to investigate the effect DOG1, PDGFRA, and KIT mutations on the prediction of the outcome for GIST management. Polymerase chain reaction was performed for KIT gene exons 9, 11, 13, and 17 and PDGFRA gene exons 12 and 18 with the genomic DNA of 46 GIST patients, and amplicons were sequenced in both directions. Immunocytochemical stainings were done by using primary antibodies. Molecular analysis revealed that the KIT mutation was observed in 63% of all cases, while the PDGFRA mutation was observed in 23.9% of cases. Significant relationships were found between age and KIT mutation, tumor location and KIT mutations, and tumor location and PDGFRA mutations (p ≤ 0.05). DOG1 positivity was detected in 65.2% of all GISTs and DOG1-positive cells had a higher KIT mutation ratio than DOG1-negative cells (p ≤ 0.05). KIT gene exon 11 mutations in DOG1-positive cells was higher than DOG1-negative cells (p ≤ 0.05). Conversely, KIT gene exon 13 mutations were higher in DOG1-negative cells than DOG1-positive cells (p ≤ 0.05). In this study, KIT mutation frequency was found similar with the European population; conversely, PDGFRA mutation frequency was similar with an Asian-Chinese-based study. KIT/PDGFRA mutations and tumor location can be used for the prediction of tumor behavior and the management of disease in GISTs. DOG1 positivity might be a candidate marker to support KIT and PDGFRA mutations, due to the higher DOG1 positivity in KIT exon 11 mutant and stomach- and small intestine-localized GISTs.

Parallelism of DOG1 expression with recurrence risk in gastrointestinal stromal tumors bearing KIT or PDGFRA mutations

Background

Gastrointestinal stromal tumors (GISTs) are characterized by mutations of KIT (v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog) or PDGFRA (platelet-derived growth factor receptor α) that may be efficiently targeted by tyrosine kinase inhibitors (TKI). Notwithstanding the early responsiveness to TKI, the majority of GISTs progress, imposing the need for alternative therapeutic strategies. DOG1 (discovered on GIST-1) shows a higher sensitivity as a diagnostic marker than KIT, however its prognostic role has been little investigated.

Methods

We evaluated DOG1 expression by immunohistochemistry (IHC) in 59 patients with GISTs, and correlated its levels with clinical and pathological features as well as mutational status. Kaplan-Meier analysis was also applied to assess correlations of the staining score with patient recurrence-free survival (RFS).

Results

DOG1 was expressed in 66 % of CD117⁺ GISTs and highly associated with tumor size and the rate of wild-type tumors. Kaplan-Meier survival analysis showed that a strong DOG1 expression demonstrated by IHC correlated with a worse 2-year RFS rate, suggesting its potential ability to predict GISTs with poor prognosis.

Conclusions

These findings suggest a prognostic role for DOG1, as well as its potential for inclusion in the criteria for risk stratification.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2111-x) contains supplementary material, which is available to authorized users.

KIT and PDGFRA mutations and the risk of GI stromal tumor recurrence

PURPOSE

Mutated KIT and platelet-derived growth factor alpha gene (PDGFRA) drive GI stromal tumor (GIST) oncogenesis, but the clinical significance of their single mutations is known incompletely.

PATIENTS AND METHODS

We identified 11 population-based series of patients with GIST through a literature search and pooled individual data from 3,067 patients treated with macroscopically complete tumor excision. Mutation analysis was done from 1,505 tumors. We analyzed associations between KIT and PDGFRA mutations and recurrence-free survival (RFS) in the subsets in which patients were treated with surgery alone.

RESULTS

We identified 301 different single mutations in KIT and 33 in PDGFRA. Patients with PDGFRA mutations had more favorable RFS than those with KIT mutations (hazard ratio, 0.34; P = .004). Only one of the 35 GISTs with KIT exon 11 duplication mutations recurred. Patients with deletions of only one codon of KIT exon 11 had better RFS than those with another deletion type, and some KIT exon 11 substitution mutations (Trp557Arg, Val559Ala, and Leu576Pro) were also associated with favorable RFS. Patients with an identical mutation had greatly variable outcomes depending on the standard prognostic factors, notably, mitotic count. Commonly used risk stratification schemes tended to overestimate the risk for recurrence in subgroups with prognostically favorable mutations.

CONCLUSION

GISTs with an identical KIT or PDGFRA mutation may have widely varying risks for recurrence. Most of the patients with PDGFRA mutations and those with KIT exon 11 duplication mutation or deletion of one codon have favorable RFS with surgery alone and are usually not candidates for adjuvant therapy.

Array-based comparative genomic hybridization analysis reveals chromosomal copy number aberrations associated with clinical outcome in canine diffuse large B-cell lymphoma

Canine Diffuse Large B-cell Lymphoma (cDLBCL) is an aggressive cancer with variable clinical response. Despite recent attempts by gene expression profiling to identify the dog as a potential animal model for human DLBCL, this tumor remains biologically heterogeneous with no prognostic biomarkers to predict prognosis. The aim of this work was to identify copy number aberrations (CNAs) by high-resolution array comparative genomic hybridization (aCGH) in 12 dogs with newly diagnosed DLBCL. In a subset of these dogs, the genetic profiles at the end of therapy and at relapse were also assessed. In primary DLBCLs, 90 different genomic imbalances were counted, consisting of 46 gains and 44 losses. Two gains in chr13 were significantly correlated with clinical stage. In addition, specific regions of gains and losses were significantly associated to duration of remission. In primary DLBCLs, individual variability was found, however 14 recurrent CNAs (>30%) were identified. Losses involving IGK, IGL and IGH were always found, and gains along the length of chr13 and chr31 were often observed (>41%). In these segments, MYC, LDHB, HSF1, KIT and PDGFRα are annotated. At the end of therapy, dogs in remission showed four new CNAs, whereas three new CNAs were observed in dogs at relapse compared with the previous profiles. One ex novo CNA, involving TCR, was present in dogs in remission after therapy, possibly induced by the autologous vaccine. Overall, aCGH identified small CNAs associated with outcome, which, along with future expression studies, may reveal target genes relevant to cDLBCL.

C-kit and PDGFRA gene mutations in triple negative breast cancer

In this study, we evaluated C-kit immunohistochemical expression and C-kit and platelet derived growth factor receptor A (PDGFRA) gene mutations in triple negative breast cancer. 171 cases were analyzed by immunohistochemical staining for the expression of C-kit and 45 cases, including 10 C-kit negative cases and 35 C-kit positive cases, were performed for C-kit gene mutations in exons 9, 11, 13 and 17 and PDGFRA gene mutations in exons 12 and 18. C-kit expression was detected in 42.1% of triple negative breast cancers. Only 1 activating mutation was detected in exon 11 of C-kit gene in 1 case. No activating mutations were found in the other 44 cases. C-kit expression is a frequent finding in triple negative breast cancers; 1 activating mutation which was also found in gastrointestinal stromal tumors was detected; a few cases might benefit from imatinib.