c-kit (CD117) expression in human tumors and its prognostic value: an immunohistochemical analysis

Expression of the Immunohistochemical Markers CK5, CD117, and EGFR in Molecular Subtypes of Breast Cancer Correlated with Prognosis

Molecular-based subclassifications of breast cancer are important for identifying treatment options and stratifying the prognosis in breast cancer. This study aimed to assess the prognosis relative to disease-free survival (DFS) and overall survival (OS) in patients with triple-negative breast cancer (TNBC) and other subtypes, using a biomarker panel including cytokeratin 5 (CK5), cluster of differentiation 117 (CD117), and epidermal growth factor receptor (EGFR). This cohort-case study included histologically confirmed breast carcinomas as cohort arm. From a total of 894 patients, 572 patients with early breast cancer, sufficient clinical data, and archived tumor tissue were included. Using the immunohistochemical markers CK5, CD117, and EGFR, two subgroups were formed: one with all three biomarkers negative (TBN) and one with at least one of those three biomarkers positive (non-TBN). There were significant differences between the two biomarker subgroups (TBN versus non-TBN) in TNBC for DFS (p = 0.04) and OS (p = 0.02), with higher survival rates (DFS and OS) in the non-TBN subgroup. In this study, we found the non-TBN subgroup of TNBC lesions with at least one positive biomarker of CK5, CD117, and/or EGFR, to be associated with longer DFS and OS.

99m-Technetium-Pertechnetat- und 99m-Technetium-Sestamibi-Szintigrafie zur Darstellung von hypofunktionellem Schilddrüsengewebe und Staging bei einem Hund mit Schilddrüsenkarzinom

Eine 10-jährige Mischlingshündin wurde aufgrund einer zervikalen Umfangsvermehrung zur Schilddrüsen-Szintigrafie vorgestellt.

Aufgrund einer zusätzlichen Hypothyreose, die einen „kalten“ Knoten vermuten ließ, und zur Metastasensuche, erfolgte neben der 99m-Technetium-Pertechnetat (Tc-Pertechnetat)-Szintigrafie eine zweite Szintigrafie mit 99m-Technetium-Sestamibi (Tc-MIBI).

Zwanzig Minuten nach intravenöser Gabe von 38 MBq Tc-Pertechnetat waren ein „heißer“ zervikaler und ein intrathorakaler Knoten mit einem „Uptake“ von 8,40 und 0,25 % sichtbar. In der zweiten Szintigrafie 20 Minuten nach intravenöser Gabe von 364 MBq Tc-MIBI und 70 Minuten nach der ersten Szintigrafie zeigten die Knoten nach Abzug der Pertechnetat-Aktivität und Zerfallskorrektur einen „Uptake“ von 0,99 und 0,03 %. Zudem stellten sich in der Schilddrüsenloge beide Schilddrüsenlappen mit einer geringen Tc-MIBI-Aufnahme dar. Das Verhältnis Tc-„Uptake“/Tc-MIBI-„Uptake“ betrug für beide Läsionen 8,48 bzw. 8,33.

Nach Exstirpation des zervikalen Tumors ergab die histopathologische Untersuchung atrophisches Schilddrüsengewebe, das von einem expansiv wachsenden gut differenzierten follikulären Schilddrüsenkarzinom fast vollständig verdrängt wurde.

Dieser Fallbericht beschreibt Durchführung, Nutzen und rechnerische Korrektur einer aufeinanderfolgenden Pertechnetat- und MIBI-Szintigrafie, die eine Darstellung von hypofunktionellem Schilddrüsengewebe ermöglichte. Die beiden heißen Knoten waren daher und aufgrund ihrer gleichen MIBI-Stoffwechselaktivität als dystopes Gewebe/Metastasen zu werten, wodurch die Hündin in das prognostisch ungünstigere WHO-Stadium IV klassifiziert werden musste. Anders als beim Menschen sollten beim Hund zur Vermeidung einer erneuten Narkose beide Szintigrafien kurz hintereinander durchgeführt werden. Eine qualitative/visuelle Beurteilung des MIBI-Szintigramms ist daher nicht sicher möglich, sodass eine quantitative Beurteilung über den „Uptake“ nach rechnerischer Korrektur der Pertechnetat-Aktivität erfolgen muss.

Colon cancer organoids using monoclonal organoids established in four different lesions of one cancer patient reveal tumor heterogeneity and different real-time responsiveness to anti-cancer drugs

Organoid culture technique has been taking center stage as a next-generation ex-vivo model due to advancement of stem cell research techniques. The importance of the laboratory-based ex vivo model has increasingly been recognized for recapitulating histological, and physioglocal conditions of in vivo microenviorment. Accordingly, the use of this technique has also broadened the understanding of intratumoral heterogeneity which is closely associated with varied drug responses observed in patients. Likewise, studies on heterogeneity within a single tumor tissue have drawn much attention. Here, we isolated 15 single clones from 4 tumor organoid lines from 1 patient at a primary passage from one patient. Each organoid line showed variable alterations in both genotype and phenotype. Furthermore, our methodological approach on drug test employing a high-throughput screening system enabled us to pinpoint the optimal time frame for anti-cancer drugs within a single tumor. We propose that our method can effectively reveal the heterogeneity of time-point in drug response, and the most optimal therapeutic strategies for individual patient.

TCOF1 upregulation in triple-negative breast cancer promotes stemness and tumour growth and correlates with poor prognosis

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with poor prognosis. By performing multiomic profiling, we recently uncovered super-enhancer heterogeneity between breast cancer subtypes. Our data also revealed TCOF1 as a putative TNBC-specific super-enhancer-regulated gene. TCOF1 plays a critical role in craniofacial development but its function in cancer remains unclear.

METHODS

Overall survival and multivariant Cox regression analyses were conducted using the METABRIC data set. The effect of TCOF1 knockout on TNBC growth and stemness was evaluated by in vitro and in vivo assays. RNA-seq and rescue experiments were performed to explore the underlying mechanisms.

RESULTS

TCOF1 is frequently upregulated in TNBC and its elevated expression correlates with shorter overall survival. TCOF1 depletion significantly inhibits the growth and stemness of basal-like TNBC, but not of mesenchymal-like cells, highlighting the distinct molecular dependency in different TNBC subgroups. RNA-seq uncovers several stem cell molecules regulated by TCOF1. We further demonstrate that KIT is a downstream effector of TCOF1 in mediating TNBC stemness. TCOF1 expression in TNBC is regulated by the predicted super-enhancer.

CONCLUSIONS

TCOF1 depletion potently attenuates the growth and stemness of basal-like TNBC. Expression of TCOF1 may serve as a TNBC prognostic marker and a therapeutic target.

Prognostic Influence of Residual Tumor-Infiltrating Lymphocyte Subtype After Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer

OBJECTIVE

This study aimed to examine the prevalence and prognostic role of tumor microenvironment (TME) in triple-negative breast cancer (TNBC) after neoadjuvant chemotherapy (NACT) through immunohistochemical characterization.

METHODS

The internal database of the Brazilian National Cancer Institute for women diagnosed with TNBC who underwent NACT and thereafter curative surgery between January 2010 and December 2014 was queried out. Core biopsy specimens and tissue microarrays containing surgical samples of TNBC from 171 and 134 women, respectively, were assessed by immunohistochemistry for CD3, CD4, CD8, CD14, CD56, CD68, CD117, FOXP3, PD-1, PD-L1, and PD-L2. Immune cell profiles were analyzed and correlated with response and survival.

RESULTS

Mean age was 50.5 years, and most cases were clinical stage III [143 cases (83.6%)]. According to the multivariate analysis, only Ki67 and clinical stage significantly influenced the pattern of response to systemic treatment (p = 0.019 and p = 0.033, respectively). None of the pre-NACT IHC markers showed a significant association with event-free survival (EFS) or overall survival (OS). As for post-NACT markers, patients with high CD14 had significantly shorter EFS (p = 0.015), while patients with high CD3 (p = 0.025), CD4 (p = 0.025), CD8 (p = 0.030), CD14 (p = 0.015), FOXP3 (p = 0.005), high CD4/FOXP3 (p = 0.034), and CD8/FOXP3 (p = 0.008) showed longer EFS. Only high post-NACT CD4 showed significantly influenced OS (p = 0.038).

CONCLUSION

The present study demonstrated that the post-NACT TIL subtype can be a determining factor in the prognosis of patients with TNBC.

Modern Imaging Technologies of Mast Cells for Biology and Medicine (Review)

Mast cells play an important role in the body defense against allergens, pathogens, and parasites by participating in inflammation development. However, there is evidence for their contributing to the pathogenesis of a number of atopic, autoimmune, as well as cardiovascular, oncologic, neurologic, and other diseases (allergy, asthma, eczema, rhinitis, anaphylaxis, mastocytosis, multiple sclerosis, rheumatoid arthritis, inflammatory gastrointestinal and pulmonary diseases, migraine, etc.). The diagnosis of many diseases and the study of mast cell functions in health and disease require their identification; so, the knowledge on adequate imaging techniques for mast cells in humans and different species of animals is of particular importance. The present review summarizes the data on major methods of mast cell imaging: enzyme histochemistry, immunohistochemistry, as well as histochemistry using histological stains. The main histological stains bind to heparin and other acidic mucopolysaccharides contained in mast cells and stain them metachromatically. Among these are toluidine blue, methylene blue (including that contained in May-Grünwald-Giemsa stain), thionin, pinacyanol, and others. Safranin and fluorescent dyes: berberine and avidin - also bind to heparin. Longer staining with histological dyes or alcian blue staining is needed to label mucosal and immature mast cells. Advanced techniques - enzyme histochemistry and especially immunohistochemistry - enable to detect mast cells high-selectively using a reaction to tryptases and chymases (specific proteases of these cells). In the immunohistochemical study of tryptases and chymases, species-specific differences in the distribution of the proteases in mast cells of humans and animals should be taken into account for their adequate detection. The immunohistochemical reaction to immunoglobulin E receptor (FcεRI) and c-kit receptor is not specific to mast cells, although the latter is important to demonstrate their proliferation in normal and malignant growth. Correct fixation of biological material is also discussed in the review as it is of great significance for histochemical and immunohistochemical mast cell detection. Fluorescent methods of immunohistochemistry and a multimarker analysis in combination with confocal microscopy are reported to be new technological approaches currently used to study various mast cell populations.

CD117/c-kit defines a prostate CSC-like subpopulation driving progression and TKI resistance

Cancer stem-like cells (CSCs) are associated with cancer progression, metastasis, and recurrence, and may also represent a subset of circulating tumor cells (CTCs). In our prior study, CTCs in advanced prostate cancer patients were found to express CD117/c-kit in a liquid biopsy. Whether CD117 expression played an active or passive role in the aggressiveness and migration of these CTCs remained an open question. In this study, we show that CD117 expression in prostate cancer patients is associated with decreased overall and progression-free survival and that activation and phosphorylation of CD117 increases in prostate cancer patients with higher Gleason grades. To determine how CD117 expression and activation by its ligand stem cell factor (SCF, kit ligand, steel factor) alter prostate cancer aggressiveness, we used C4-2 and PC3-mm human prostate cancer cells, which contain a CD117+ subpopulation. We demonstrate that CD117+ cells display increased proliferation and migration. In prostaspheres, CD117 expression enhances sphere formation. In both 2D and 3D cultures, stemness marker gene expression is higher in CD117+ cells. Using xenograft limiting dilution assays and serial tumor initiation assays, we show that CD117+ cells represent a CSC population. Combined, these data indicate that CD117 expression potentially promotes tumor initiation and metastasis. Further, in cell lines, CD117 activation by SCF promotes faster proliferation and invasiveness, while blocking CD117 activation with tyrosine kinase inhibitors (TKIs) decreased progression in a context-dependent manner. We demonstrate that CD117 expression and activation drives prostate cancer aggressiveness through the CSC phenotype and TKI resistance.

Immunohistochemical study of CD117 in various cutaneous melanocytic lesions

The aim of the present study was to carried out a comparative immunohistochemical evaluation of CD117 (c-Kit), a biomarker that evaluates both tumor progression and prognosis, in different melanocytic lesions, to emphasize the significance of this biomarker in malignant melanoma (MM). The study was performed on 55 cases, represented by a control group, which included 5 cases of simple nevi and 5 cases of dysplastic nevi, as well as a study group consisting of 35 cases of primary MM and 10 metastases (one intestinal, 3 cutaneous - one satellite and two distant as well as 6 in the lymph nodes). The study group included 15 cases of superficial spreading melanoma (SSM), 10 cases of nodular melanoma (NM), 3 lentigo maligna melanoma (LMM), 3 cases of acral lentiginous melanoma (ALM) and 4 cases of amelanotic MM. CD117 was found to be massively involved in the process of tumorigenesis of cutaneous malignancies, being immunohistochemically undetectable in benign neural lesions, but densely expressed in dysplastic lesions and in situ melanoma areas. In invasive cutaneous MMs, CD117 expression tended to decrease with neoplasia progression proceding into the tumorigenic, vertical growth phase, being lower in the profound dermal component of tumors and in nodular MMs. To eliminate the epidermal barriers and gain a proliferative advantage to allow the transition to the vertical growth phase, it seems that MM should lose expression of c-Kit. Cutaneous metastases were found to express CD117 at a level comparable to their primary tumors, suggesting that other mechanisms interfere directly with the metastatic process and not loss of c-Kit expression by itself. CD117 overexpression in cutaneous melanocytic lesions correlates significantly with increased immunostaining intensity, suggesting that the immunohistochemical evaluation of CD117 may be a good method for screening patients, who could benefit from personalized therapy with tyrosine kinase inhibitors.

Expression frequency of c-kit isoforms and its prognostic potential in canine mammary tumours

KIT is a tyrosine kinase receptor involved in carcinogenesis. Two alternatively spliced transcripts, differed from presence of four amino acids (GNSK) at exon 9 of c-kit, were identified in various human tumours and canine hemangiosarcoma (HSA). The biological function and clinical implications of these isoforms have not yet been elucidated in canine tumours. The current study aimed to validate the expression profile and ultimately to evaluate the correlation of c-kit isoform levels with clinicopathological factors of canine mammary tumours (CMTs). In total, the expression profiles of c-kit isoforms in 196 samples obtained from normal mammary glands (NMGs) of healthy controls and dogs with CMTs, benign and malignant CMTs, and HSAs were determined by polymerase chain reaction (PCR) and quantified via real-time PCR. Overall, the expression levels of the two isoforms were equivalent in NMGs, whereas the GNSK^- /GNSK⁺ ratio sharply increased to 7.44- and 8.33-fold, indicating abundant GNSK^- isoforms in benign and malignant CMTs, respectively. However, a significant decrease in GNSK^- expression was detected in dogs with high-grade malignant CMTs (mCMTs) and with metastatic CMTs compared with expression in those with a lower grade and non-metastatic CMTs. In addition, the median survival time was shorter in mCMT canines with a lower GNSK^- /GNSK⁺ ratio than that in mCMT canines with a higher ratio (899 days vs 1534 days). In conclusion, two c-kit isoforms are ubiquitously expressed with great variability in HSAs and CMTs with both benign and malignant status. The GNSK^- /GNSK⁺ ratio could serve as a prognostic indicator for dogs with mCMTs.

CD117/c-kit in Cancer Stem Cell-Mediated Progression and Therapeutic Resistance

Metastasis is the primary cause of cancer patient morbidity and mortality, but due to persisting gaps in our knowledge, it remains untreatable. Metastases often occur as patient tumors progress or recur after initial therapy. Tumor recurrence at the primary site may be driven by a cancer stem-like cell or tumor progenitor cell, while recurrence at a secondary site is driven by metastatic cancer stem cells or metastasis-initiating cells. Ongoing efforts are aimed at identifying and characterizing these stem-like cells driving recurrence and metastasis. One potential marker for the cancer stem-like cell subpopulation is CD117/c-kit, a tyrosine kinase receptor associated with cancer progression and normal stem cell maintenance. Further, activation of CD117 by its ligand stem cell factor (SCF; kit ligand) in the progenitor cell niche stimulates several signaling pathways driving proliferation, survival, and migration. This review examines evidence that the SCF/CD117 signaling axis may contribute to the control of cancer progression through the regulation of stemness and resistance to tyrosine kinase inhibitors.

Giant gastrointestinal stromal tumour of the stomach: a case report with surgical treatment

We report a case of giant gastrointestinal stromal tumour of the stomach in a 71-year-old woman, with emphasis on its going through surgical resection. The physical examination and radiological findings revealed that a giant mass occupied most of the abdominal cavity. The patient underwent an en-block resection of the mass, partial resection of the distal stomach and Billroth II gastrojejunostomy. The pathological diagnosis was gastrointestinal stromal tumour. The patient had a long-term disease-free survival. We emphasise that complete surgical resection is the only effective radical treatment approach for giant gastrointestinal stroma of the stomach. In some cases, we still have the opportunity for resection of these tumours because of their expansive growth, even though the lesions are very large.

Prognostic significance of CD117 expression and TP53 missense mutations in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is extremely aggressive and associated with poor prognosis. There are no known predictive or prognostic markers for TNBC. Inhibition of tumor protein P53 (TP53) has been demonstrated to increase the levels of cluster of differentiation 117 (CD117) in human colorectal cancer cells. However, the function of TP53 in the regulation of CD117 in TNBC has, to the best of our knowledge, not been reported. In the present study, the association between the expression of CD117 protein and TP53 mutations was investigated, and their prognostic value in patients with TNBC was assessed. A total of 58 TNBC and 48 non-TNBC breast cancer tissue samples were assessed for the expression of CD117, p53 and TP53 mutations. The marker of proliferation Ki-67 (MKI67) proliferation index and vascular invasion index (obtained by measuring D2-40 and CD34) was investigated via immunohistochemistry, and mutations in exons 4–8 of TP53 were measured using direct sequencing. Associations between CD117 and p53 levels or TP53 mutations and clinical parameters were statistically evaluated. The rates of CD117 or MKI67 positivity, CD117⁺/TP53 missense mutation⁺, TP53 missense mutations or recurrence were significantly higher in patients with TNBC than in patients with non-TNBC. In TNBC tissues, the presence of CD117 was associated with TP53 missense mutations (P=0.031), vascular invasion, recurrence and MKI67. CD117⁺/TP53 missense mutation⁺ also associated with vascular invasion, recurrence and MKI67. Under univariate analysis, MKI67, vascular invasion, CD117, CD117⁺/TP53 missense mutation⁺ and TP53 missense mutations were associated with the overall survival of patients with TNBC. Multivariate analysis revealed that vascular invasion and CD117⁺/TP53 missense mutation⁺ in primary tumors were independent prognostic factors in patients with TNBC. In conclusion, CD117⁺/TP53 missense mutation⁺ was associated with MKI67, vascular invasion and tumor recurrence in TNBC. The presence of CD117 and TP53 missense mutations together in the primary tumors was an independent prognostic factor for survival of patients with TNBC.

Altered expression of cytokeratin 7 and CD117 in transitional mucosa adjacent to human colorectal cancer

The multi-step progression of colorectal cancer through precancerous lesions (adenoma and dysplasia) is associated with cumulative molecular alterations, a number of which have also been demonstrated to be present in morphologically normal transitional mucosa adjacent to colorectal cancer. The cytoskeletal protein cytokeratin 7 (CK7) and the receptor tyrosine kinase, KIT proto-oncogene receptor tyrosine kinase (CD117), encoded by the proto-oncogene c-Kit, are lacking in normal colorectal crypt epithelium and are aberrantly expressed in a subset of colorectal cancer. The aim of the present study was to evaluate the expression of CK7 and CD117 in morphologically normal transitional mucosa adjacent to colorectal cancer. Immunohistochemical staining for CK7 and CD117 was performed in the mucosa adjacent to five groups of surgically resected colorectal tumors [low-grade adenoma, high-grade adenoma, mucosal adenocarcinoma, small-sized invasive adenocarcinoma (≤2 cm) and large-sized invasive adenocarcinoma (>2 cm)]. CK7 was expressed in the mucosa adjacent to a subset of colorectal tumors, and the positivity ratio increased according to tumor grade from low-grade adenoma up to small-sized invasive adenocarcinoma (61.2%). However, the positivity ratio of CK7 in the mucosa adjacent to the large-sized invasive adenocarcinoma (25.0%) was significantly lower compared with that of the next lower grade. CD117 was also expressed in the mucosa adjacent to a subset of colorectal tumors. In contrast to CK7, the positivity ratio of CD117 increased according to tumor grade from low-grade adenoma all the way through to the large-sized invasive adenocarcinoma (45.0%). Based on these results, the mechanism of CK7 and CD117 expression in the transitional mucosa adjacent to colorectal cancer may be different, and analysis of their individual expression may provide novel insights into the development and progression of colorectal cancer.

Accuracy of c-KIT in Lung Cancer Prognosis; a Systematic Review Protocol" instead of c-KIT Expression in Lung Cancer Prognostic Evaluation - a Systematic Review Protocol

BACKGROUND

Extensive efforts have been made to investigate c-KIT expression in lung cancer specimens and its correlation with clinical outcomes, but the issue remains unresolved. Thus, this study will be conducted to clarify the prognostic value of c-KIT expression in lung cancer patients.

MATERIALS AND METHODS

We will search Pubmed, SCOPUS, and ISI web of sciences with no restriction of language. Studies with any design (except case reports or case series) evaluating correlations of c-KIT expression with survival or outcome in patients with lung cancer will be included. The outcome measures will include all types of survival indexes, including overall survival rate and disease free survival using Kaplan-Meier analysis and hazard ratios. Study selection and data extraction will be performed by two independent researchers. Quality assessment (assessment of risk of bias) and data synthesis will be implemented using Stata software version 11.1.

RESULTS

No ethical issues are predicted. These findings will be published in a peer-reviewed journal and presented at national and international conferences.

CONCLUSIONS

This systematic review protocol is registered in the PROSPERO International Prospective Register of Systematic Reviews, registration number = CRD42015023391.

CD117⁺ cells in the circulation are predictive of advanced prostate cancer

Circulating tumor cells (CTCs) are associated with cancer progression, aggressiveness and metastasis. However, the frequency and predictive value of CTCs in patients remains unknown. If circulating cells are involved in tumor aggressiveness and metastasis, then cell levels should decline upon tumor removal in localized cancer patients, but remain high in metastatic patients. Accordingly, proposed biomarkers CD117/c-kit, CD133, CXCR4/CD184, and CD34-positive cell percentages in the blood of patients undergoing radical prostatectomy for localized cancer were assessed by flow cytometry prior to intervention and 1–3 months postoperatively. Only circulating CD117⁺ cell percentages decreased after radical prostatectomy, increased with cancer progression and correlated with high PSA values. Notably, postoperative CD117⁺ levels did not decrease in patients experiencing biochemical recurrence. In a xenograft model, CD117-enriched tumors were more vascularized and aggressive. Thus, CD117 expression on CTCs promotes tumor progression and could be a biomarker for prostate cancer diagnosis, prognosis, and/or response to therapy.

Expression of Stem Cell Markers in Preinvasive Tubal Lesions of Ovarian Carcinoma

In order to better understand the ovarian serous carcinogenic process with tubal origin, we investigated the expression of stem cell markers in premalignant tubal lesions (serous tubal intraepithelial carcinoma or STIC). We found an increased stem cell marker density in the normal fallopian tube followed by a high CD117 and a low ALDH and CD44 expression in STICs raising the question of the role of the stem cell markers in the serous carcinogenic process.

KIT Signaling Promotes Growth of Colon Xenograft Tumors in Mice and Is Up-Regulated in a Subset of Human Colon Cancers

BACKGROUND & AIMS

Receptor tyrosine kinase (RTK) inhibitors have advanced colon cancer treatment. We investigated the role of the RTK KIT in development of human colon cancer.

METHODS

An array of 137 patient-derived colon tumors and their associated xenografts were analyzed by immunohistochemistry to measure levels of KIT and its ligand KITLG. KIT and/or KITLG was stably knocked down by expression of small hairpin RNAs from lentiviral vectors in DLD1, HT29, LS174T, and COLO320 DM colon cancer cell lines, and in UM-COLON#8 and POP77 xenografts; cells transduced with only vector were used as controls. Cells were analyzed by real-time quantitative reverse transcription polymerase chain reaction, single-cell gene expression analysis, flow cytometry, and immunohistochemical, immunoblot, and functional assays. Xenograft tumors were grown from control and KIT-knockdown DLD1 and UM-COLON#8 cells in immunocompromised mice and compared. Some mice were given the RTK inhibitor imatinib after injection of cancer cells; tumor growth was measured based on bioluminescence. We assessed tumorigenicity using limiting dilution analysis.

RESULTS

KIT and KITLG were expressed heterogeneously by a subset of human colon tumors. Knockdown of KIT decreased proliferation of colon cancer cell lines and growth of xenograft tumors in mice compared with control cells. KIT knockdown cells had increased expression of enterocyte markers, decreased expression of cycling genes, and, unexpectedly, increased expression of LGR5 associated genes. No activating mutations in KIT were detected in DLD1, POP77, or UM-COLON#8 cells. However, KITLG-knockdown DLD1 cells formed smaller xenograft tumors than control cells. Gene expression analysis of single CD44(+) cells indicated that KIT can promote growth via KITLG autocrine and/or paracrine signaling. Imatinib inhibited growth of KIT(+) colon cancer organoids in culture and growth of xenograft tumors in mice. Cancer cells with endogenous KIT expression were more tumorigenic in mice.

CONCLUSIONS

KIT and KITLG are expressed by a subset of human colon tumors. KIT signaling promotes growth of colon cancer cells and organoids in culture and xenograft tumors in mice via its ligand, KITLG, in an autocrine or paracrine manner. Patients with KIT-expressing colon tumors can benefit from KIT RTK inhibitors.

Epithelial ovarian cancer with CD117 phenotype is highly aggressive and resistant to chemotherapy

AIM

CD117 expression has a pathogenic role in many malignancies, including ovarian carcinoma. The aim of the present study was to examine the correlation of stemness-associated marker CD117 with the clinicopathologic features of epithelial ovarian cancer and patient survival.

MATERIAL AND METHODS

The analysis included 240 primary ovarian carcinomas (OC) diagnosed during the period from 2005 to 2011 in the region of South Serbia. Age, pathohistological characteristics, presence and size of residual tumor, choice of therapy and response to the therapy were studied.

RESULTS

Residual tumors were more frequently present in the patients with positive CD117 expression (18.1% vs 8.0%; P < 0.05). Chemotherapy according to paclitaxel/carboplatin protocol was more frequent in the patients with positive CD117 expression (70.9% vs 54.2%; P < 0.05), while carboplatin monotherapy was more frequent in the patients with negative CD117 expression (18.0% vs 6.4%; P < 0.05). Median survival time in patients with CD117-positive mucinous and endometrioid OC was significantly shorter, at 20 and 26.8 months, respectively. Median survival in serous OC was not related to CD117 expression.

CONCLUSION

Residual tumors and chemotherapy treatment were more frequent in patients with positive CD117 expression. The outcome was dependent on the type of OC; a worse outcome, including a shorter survival, was documented in the mucinous and endometrioid OC cases.

c-Kit is suppressed in human colon cancer tissue and contributes to L1-mediated metastasis

The transmembrane neural cell adhesion receptor L1 is a Wnt/β-catenin target gene expressed in many tumor types. In human colorectal cancer, L1 localizes preferentially to the invasive front of tumors and when overexpressed in colorectal cancer cells, it facilitates their metastasis to the liver. In this study, we investigated genes that are regulated in human colorectal cancer and by the L1-NF-κB pathway that has been implicated in liver metastasis. c-Kit was the most highly suppressed gene in both colorectal cancer tissue and the L1-NF-κB pathway. c-Kit suppression that resulted from L1-mediated signaling relied upon NF-κB, which directly inhibited the transcription of SP1, a major activator of the c-Kit gene promoter. Reconstituting c-Kit expression in L1-transfected cells blocked the biological effects conferred by L1 overexpression in driving motility and liver metastasis. We found that c-Kit expression in colorectal cancer cells is associated with a more pronounced epithelial morphology, along with increased expression of E-cadherin and decreased expression of Slug. Although c-Kit overexpression inhibited the motility and metastasis of L1-expressing colorectal cancer cells, it enhanced colorectal cancer cell proliferation and tumorigenesis, arguing that separate pathways mediate tumorigenicity and metastasis by c-Kit. Our findings provide insights into how colorectal cancer metastasizes to the liver, the most common site of dissemination in this cancer.

Protein kinase C-δ-mediated recycling of active KIT in colon cancer

PURPOSE

Abnormal signaling through receptor tyrosine kinase (RTK) moieties is important in tumorigenesis and drug targeting of colorectal cancers. Wild-type KIT (WT-KIT), a RTK that is activated upon binding with stem cell factor (SCF), is highly expressed in some colon cancers; however, little is known about the functional role of SCF-dependent KIT activation in colon cancer pathogenesis. We aimed to elucidate the conditions and roles of WT-KIT activation in colon cancer tumorigenesis.

EXPERIMENTAL DESIGN

Colorectal cancers with KIT expression were characterized by immunoblotting and immunohistochemistry. The biologic alterations after KIT-SCF binding were analyzed with or without protein kinase C (PKC) activation.

RESULTS

We found that WT-KIT was expressed in a subset of colon cancer cell lines and was activated by SCF, leading to activation of downstream AKT and extracellular signal-regulated kinase (ERK) signaling pathways. We also showed that KIT expression gradually decreased, after prolonged SCF stimulation, due to lysosomal degradation. Degradation of WT-KIT after SCF binding was significantly rescued when PKC was activated. We also showed the involvement of activated PKC-δ in the recycling of WT-KIT. We further showed that a subset of colorectal cancers exhibit expressions of both WT-KIT and activated PKC-δ and that expression of KIT is correlated with poor patient survival (P = 0.004).

CONCLUSIONS

Continuous downstream signal activation after KIT-SCF binding is accomplished through PKC-δ-mediated recycling of KIT. This sustained KIT activation may contribute to tumor progression in a subset of colon cancers with KIT expression and might provide the rationale for a therapeutic approach targeting KIT.

A rare giant gastrointestinal stromal tumor of the stomach traversing the upper abdomen: a case report and literature review

We present the case of a 66-year-old woman with a huge gastrointestinal stromal tumor of the stomach that traversed her upper abdomen. The predominant abdominal sign was a huge, palpable mass, but there were no other distinctive findings in her physical examination or her routine blood workup, including biochemical markers. It was difficult to judge the origin of the mass upon imaging. Furthermore, radiological findings revealed that the mass had a complex relationship with many major blood vessels. An exploratory laparotomy revealed a huge tumor protruding from the anterior wall of the stomach fundus, on the lesser curvature of the stomach, measuring approximately 21 × 34 × 11 cm in diameter and weighing 5.5 kg. A complete resection was performed and the tumor was characterized on immunohistochemistry as a gastrointestinal stromal tumor of the stomach. Preoperative diagnosis of gastrointestinal stromal tumors can be difficult, and we hope that the presentation of this rare case and literature review will benefit other diagnosing clinicians having similar problems.