Prediction of MGMT promotor methylation status in glioblastoma by contrast-enhanced T1-weighted intensity image.

Background: The study aims to explore MRI phenotypes that predict glioblastoma's (GBM) methylation status of the promoter region of MGMT gene (pMGMT) by qualitatively assessing contrast-enhanced T1-weighted intensity images. Methods: A total of 193 histologically and molecularly confirmed GBMs at the Kansai Network for Molecular Diagnosis of Central Nervous Tumors (KANSAI) were used as an exploratory cohort. From the Cancer Imaging Archive/Cancer Genome Atlas (TCGA) 93 patients were used as validation cohorts. "Thickened structure" was defined as the solid tumor component presenting circumferential extension or occupying >50% of the tumor volume. "Methylated contrast phenotype" was defined as indistinct enhancing circumferential border, heterogenous enhancement, or nodular enhancement. Inter-rater agreement was assessed, followed by an investigation of the relationship between radiological findings and pMGMT methylation status. Results: Fleiss's Kappa coefficient for "Thickened structure" was 0.68 for the exploratory and 0.55 for the validation cohort, and for "Methylated contrast phenotype," 0.30 and 0.39, respectively. The imaging feature, the presence of "Thickened structure" and absence of "Methylated contrast phenotype," was significantly predictive of pMGMT unmethylation both for the exploratory (p = .015, odds ratio = 2.44) and for the validation cohort (p = .006, odds ratio = 7.83). The sensitivities and specificities of the imaging feature, the presence of "Thickened structure," and the absence of "Methylated contrast phenotype" for predicting pMGMT unmethylation were 0.29 and 0.86 for the exploratory and 0.25 and 0.96 for the validation cohort. Conclusions: The present study showed that qualitative assessment of contrast-enhanced T1-weighted intensity images helps predict GBM's pMGMT methylation status.

The Add-On Effect of Fluorouracil, Epirubicin, and Cyclophosphamide Regimens for Neoadjuvant Chemotherapy in Human Epidermal Receptor 2 (HER2)-Positive Breast Cancer: A Single-Center Retrospective Study.

BACKGROUND: The addition of pertuzumab to trastuzumab in neoadjuvant chemotherapy (NAC) for anti-human epidermal receptor 2 (HER2) positive breast cancer has shown a significant improvement in the pathologic complete response (pCR) rate. However, the add-on effect of an anthracycline-based regimen (standard-of-care regimen) remains unclear. In this retrospective, observational study, participants received pertuzumab combination therapy as NAC for HER2-positive primary breast cancer. METHODS: This study was conducted from January 1, 2020, to December 31, 2022. Patients who had not received at least three courses of pertuzumab owing to adverse events or those who had received preoperative radiotherapy were excluded. RESULTS: The pCR rate was 35.3% (12/34 patients). The pCR group had a significantly higher percentage of histopathologic grade III (1/11 patients, p=0.030) and a significantly higher percentage of hormone receptor-negative patients (7/12 patients, p=0.015) than the non-pCR group. The non-pCR group had a significantly higher incidence of vascular invasion than the pCR group (7/22 patients, p=0.036). Menopausal status, stage, and ki-67 values were not significantly different between the two groups. CONCLUSIONS: This study suggests an unlikely add-on effect of an anthracycline-based regimen for NAC in HER2-positive breast cancer. Moreover, our results support that the pCR rate is high in patients with hormone receptor-negative, HER2-positive breast cancer.

Surgical Treatment of Secondary Pneumothorax-Complicated Interstitial Lung Disease.

INTRODUCTION: To investigate the feasibility of early surgical treatment and perioperative steroid use in patients with interstitial lung disease (ILD) complicated by pneumothorax. METHODS: We retrospectively examined data, including patient characteristics, laboratory findings, surgical treatment details, postoperative complications, and deaths, of nine patients with ILD complicated by secondary pneumothorax. The patients had been treated at our hospital during the past 10 years. RESULTS: All nine patients were male (median age, 69.0 years). A total of nine patients had a histopathologic diagnosis of ILD after surgery. Of these, five were clinically diagnosed with ILD before surgery. Collagen disease was diagnosed in one case, drug-induced in one case, and idiopathic ILD (IILD) in three cases. All nine patients were diagnosed with postoperative ILD, including one case of collagen disease, one case of drug-induced, three cases of idiopathic pulmonary fibrosis (IPF)/cryptogenic fibrosing alveolitis, one case of nonspecific interstitial pneumonia (NSIP), and three cases of cryptogenic organizing pneumonia (COP). Regarding preoperative clinical characteristics, the performance status (PS) was 0 or 1 in all patients. Overall, three patients received oxygen (0-3 L/min), whereas steroids were administered to five patients. The mean drainage period was 23.5 days, and this was consistent with the time taken from pneumothorax occurrence to surgery. Video-assisted thoracic surgery (VATS) and thoracoscopic-assisted surgery were performed in seven and two patients, respectively. No postoperative recurrence or surgery-related deaths occurred. CONCLUSIONS: Early surgery for secondary pneumothorax complicated by ILD may be a viable option for patients in good preoperative condition. For patients who are preoperatively treated with steroids, continued use of steroids should be carefully considered.

Two Cases of SMARCA4-Deficient Non-small Cell Lung Cancer (NSCLC) with Improved Performance Status (PS) after Treatment with Immune Checkpoint Inhibitors (ICIs).

SWItch/Sucrose Non-Fermentable (SWI/SNF)-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4 (SMARCA4) mutations are commonly reported in non-small cell lung cancer (NSCLC) and are associated with a poor prognosis. There is insufficient evidence regarding the efficacy of immune checkpoint inhibitors (ICIs) in SMARCA4-deficient NSCLC patients with poor performance status (PS). We report two cases of advanced SMARCA4-deficient NSCLC treated with ICIs, in which marked regression of the tumor and improved general condition of the patients were achieved.

Low-grade papillary Schneiderian carcinoma with TP53 mutation: a case report and review of the literature.

BACKGROUND: Low-grade papillary Schneiderian carcinoma (LGPSC) is a relatively new entity of the sinonasal tract and is characterized by a bland morphology simulating sinonasal papilloma, invasive growth pattern with pushing borders, and aggressive clinical behavior with multiple recurrences and metastatic potential. Recently, DEK::AFF2 fusions were identified in LGPSC. However, some LPGSCs lack DEK::AFF2 fusion, and the molecular features of these tumors have not been clarified. CASE PRESENTATION: A 69-year-old man presented with a discharge of pus from his left cheek. Computed tomography revealed a mass involving the left maxillary sinus, ethmoid sinus, and nasal cavity with the destruction of the orbital wall. The biopsy specimens showed that the tumor had a predominantly exophytic, papillary growth and did not have an apparent stromal invasion. The tumor was composed of multilayered epithelium that showed bland morphology with a round to polygonal shape, abundant eosinophilic cytoplasm, and uniform nuclei. Dense neutrophilic infiltrates were focally present. Immunohistochemically, CK5/6 was strongly and diffusely positive, and p16 was negative. p63 was mainly positive in the basal layer, and EMA was predominantly expressed in the outermost cell layer. DNA-based targeted sequencing showed TP53 R175H mutation, whereas neither EGFR nor KRAS mutation was identified. Reverse transcription polymerase chain reaction and fluorescence in situ hybridization revealed no DEK::AFF2 fusion. CONCLUSIONS: We describe the first case of TP53-mutant LGPSC and review the literature. LGPSC is a genetically heterogeneous entity, and the recognition of this rare entity and comprehensive assessment of clinicopathological and molecular findings are crucial for the correct pathological diagnosis and clinical management.

[Successful rituximab treatment of TAFRO syndrome refractory to glucocorticoids and tocilizumab].

A 53-year-old man was presented with fever, eyelid edema, and thrombocytopenia. Based on examination outcomes, he was diagnosed with immune thrombocytopenia. He was prescribed prednisolone (PSL) at 0.5 mg/kg/day; subsequently, his platelet count improved and fever improved. PSL dose was tapered and stopped without relapse. However, 1 month later, the patient presented to our hospital with fever, generalized edema, thrombocytopenia, and acute renal failure. Computed tomography revealed multiple lymphadenopathies, hepatomegaly, pleural effusion, and ascites. Bone marrow biopsy indicated reticulin fibrosis, and lymph node biopsy revealed mixed-type Castleman disease. Based on these findings, he was diagnosed with grade 5 TAFRO syndrome (very severe). Steroid pulse therapy and tocilizumab were ineffective in improving his condition. Therefore, rituximab was administered instead of tocilizumab, and his condition eventually improved. The optimal treatment for TAFRO syndrome is yet to be established. If tocilizumab is ineffective as the second-line treatment, then rituximab might be effective.

Subcellular localization of hTERT in breast cancer: insights into its tumorigenesis and drug resistance mechanisms in HER2-immunopositive breast cancer.

Human telomerase reverse transcriptase (hTERT) is highly expressed in various cancers, including breast cancer. Although telomere elongation is an essential role for hTERT, the nuclear export after oxdative stress has also been shown in several cancer cell lines and is associated with drug-resistance in vitro. As only a few reports focused on the subcellular localization of hTERT in clinical specimens, we performed immunohistochemistry (IHC) and analyzed the correlation between intracellular hTERT expression and the clinicopathological characteristics to identify the clinical significance of hTERT subcellular expression in breast cancers. 144 invasive breast cancers classified by IHC subtype without primary systemic therapy (PST), were selected from a surgical resection cohort and were immunostained for hTERT, p-STAT3, p-AKT and p-ERK. The nuclear and/or cytoplasmic staining intensity and proportion of hTERT were scored and compared with clinicopathological parameters. The nuclear hTERT expression was significantly correlated with HER2 expression (p = 0.00156), and the scores were significantly correlated with p-STAT3 and p-AKT expression scores (r = 0.532, p = 0.000587 and r = 0.345, p = 0.0339, respectively) in the HER2-immunopositive breast cancer including luminal-HER2 and HER2 subtypes. Furthermore, hTERT was expressed more in cytoplasm in the specimens after PST than those before PST, and the score tended to be negatively correlated with tumor shrinkage rate in HER2 subtype (r = -0.593, p = 0.0705). These results suggest that nuclear and/or cytoplasmic hTERT may play a different role before and after PST including the tumorigenesis and drug-resistance in breast cancer. Suppression of cytoplasmic hTERT expression may lead to more effective strategy for drug-resistant HER2 subtype in breast cancer.

Intraoperative rapid immunohistochemistry with noncontact antibody mixing for undiagnosed pulmonary tumors.

Knowledge of the histologic type and primary origin of pulmonary tumors is essential when preparing a surgical strategy. Intraoperative diagnosis of hematoxylin and eosin (H&E)-stained frozen sections is the gold standard, but reliable pathology requires time-consuming immunohistochemistry (IHC) to distinguish among histological types/organ origins and to analyze molecular status. The aim of this study was to evaluate the clinical reliability of a new rapid-IHC technique for intraoperative diagnosis of pulmonary tumors. In total, 169 patients with undiagnosed pulmonary tumors were enrolled in a multicenter prospective observational study. At three institutes, pulmonary tumor samples were collected through core needle biopsy and/or surgery to determine surgical strategies. Using a new device for rapid IHC, we applied a high-voltage, low-frequency alternating current (AC) field, which mixes the available antibody as the voltage is switched on/off. Rapid IHC can provide tumor histologic type/origin diagnoses within 20 min, as opposed to the 3-6 h required for conventional IHC. No false diagnoses of malignancy were rendered in any of the cases when using simple H&E staining. With H&E staining alone, the overall definitive diagnosis rate, the rate of defined tumor origin, and the rate of determined histological type were 76.92%, 85.80%, and 90.53%, respectively. When rapid IHC was added, those rates were significantly improved to 88.76%, 94.67%, and 91.72%, respectively. By providing prompt and accurate intraoperative histological/molecular analysis, rapid IHC driven by AC mixing could serve as an effective clinical tool guiding the surgical strategy for undiagnosed pulmonary tumors.

A case of percutaneous transhepatic stomal varices embolization and partial splenic artery embolization for rectal cancer after CAPOX/BEV chemotherapy: the summary of the stomal varices related to oxaliplatin administration.

Capecitabine and oxaliplatin (CAPOX) plus bevacizumab (BEV) therapy (CAPOX/BEV) is a standard treatment recommended as the first-line treatment for colorectal cancer recurrence. Recently, sinusoidal obstruction syndrome (SOS) and resulting portal hypertension have been reported as important side effects of oxaliplatin. We herein report a rectal cancer patient who underwent percutaneous transhepatic stoma variceal embolization (PTO) and partial splenic artery embolization (PSE) for stomal variceal bleeding and splenomegaly due to portal hypertension caused by SOS after CAPOX therapy. A 43-year-old man who underwent robot-assisted laparoscopic abdominoperineal resection for advanced lower rectal cancer was started on CAPOX/BEV therapy for early recurrence 1 month after surgery. In the sixth course, splenomegaly rapidly worsened, stomal varices appeared, and the stoma began bleeding. At 5 months after the appearance of stomal varices, the splenomegaly worsened, the frequency of stomal bleeding increased, and PTO was performed. Five months later, PSE was performed for splenomegaly and thrombocytopenia. At 5 months since the PSE, the stoma bleeding has not recurred, and the thrombocytopenia has been corrected. The patient has been able to continue chemotherapy. We suggest that staged treatment by PTO and PSE be considered an important treatment option for stomal varices and splenomegaly associated with SOS.

Contrast-enhanced ultrasonography for the diagnosis of spontaneous necrosis of hepatocellular carcinoma: A report of 2 cases.

Spontaneous necrosis of hepatocellular carcinoma (HCC) is rare and difficult to diagnose preoperatively if it occurs before the definitive diagnosis of HCC; this is because spontaneous necrosis of HCC exhibits various patterns in imaging studies. We compared imaging and pathological findings, and examined the possibility of diagnosing spontaneous necrosis of HCC using contrast-enhanced ultrasonography (CEUS). We experienced 2 cases of spontaneous necrosis of HCC. In case 1, spontaneous necrosis occurred after HCC diagnosis, while in case 2 it occurred before the first admission. The tumor in case 2 contained internal nodules and outer fibrous tissue. CEUS revealed a vascular spot in the hypovascular area during the vascular phase and a complete defect during the Kupffer phase. These findings accorded with the pathological findings and may be important for diagnosing spontaneous necrosis of HCC.

Gastro-colic Fistula-associated Hypersplenism Causes Pancytopenia in a Patient with Crohn's Disease.

A 24-year-old woman was admitted to our hospital due to abdominal pain and a high fever. She was diagnosed with ileocolonic Crohn's disease (CD), complicated with a gastro-colic fistula and splenomegaly. After initial treatment with an infliximab-biosimilar, all blood cell line counts markedly decreased. Three-dimensional reconstructed computed tomography revealed splenic vein narrowing. Thus, her pancytopenia was deemed to have likely been caused by hypersplenism. Surgery was performed, and clinical remission was maintained without pancytopenia. This is the first report of a CD patient with pancytopenia caused by hypersplenism that was triggered by gastro-colic fistula-associated splenic vein obstruction.

Successful Multidisciplinary Treatment with Laparoscopic Hepatectomy and Adjuvant Therapy for Metachronous Solitary Hepatic Metastasis after Excision of a Primary Anorectal Malignant Melanoma: A Case Report.

Anorectal malignant melanoma (ARMM) is extremely rare and generally lethal, irrespective of the treatment administered. The disease is often diagnosed late, metastases being present in approximately two-thirds of patients at the time of initial diagnosis. Solitary metastasis of ARMM to a distant organ is exceedingly rare. A 76-year-old woman with a history of laparoscopic abdominoperineal resection of an ARMM 13 months previously, was found to have a solitary liver metastasis in the follow-up computed tomography. A preoperative work-up showed no other distant metastases nor contraindication to surgery. It was therefore considered that resection was indicated. The metachronous solitary liver metastasis from an ARMM was treated by laparoscopic wedge hepatectomy of the eighth segment 18 months after excision of her primary ARMM. Adjuvant therapy with pembrolizumab was initiated and continued at 6-week intervals. The patient has not exhibited any immune related Adverse Effects (irAE) during or subsequent to treatment with pembrolizmab and has now completed 12 months of adjuvant pembrolizumab therapy, having survived 33 months from the initial operation for primary ARMM, and remaining recurrence-free 14 months after hepatectomy. ARMM is extremely rare and resection of a metachronous solitary metastasis followed by adjuvant therapy has not previously been reported. We hope this case will be useful for clinicians who might treat similar patients.

Amyloid deposition at the carotid artery in an ATTRwt amyloidosis patient: a case report.

Systemic amyloidosis is a diseased condition where misfolded proteins deposit in various organs in the form of amyloids, and transthyretin deposition, termed ATTR amyloidosis, can be either an age-related amyloid formation from misfolded wild-type TTR (ATTRwt) or by hereditary TTR malfunction due to mutation in the TTR gene (ATTRv). Although ATTRwt amyloidosis can cause various diseases, such as cardiac failure, conduction disturbances, arrhythmias and carpal tunnel syndrome, it is still under-recognised considering its clinical significance. Here the authors report a case of ATTRwt amyloidosis leading to carotid stenosis requiring surgical intervention. To the best of our knowledge, the current report is the first that described histopathological evidence of amyloid deposition in the carotid artery due to ATTRwt amyloidosis.

Correlation of T1- to T2-weighted signal intensity ratio with T1- and T2-relaxation time and IDH mutation status in glioma.

The current study aimed to test whether the ratio of T1-weighted to T2-weighted signal intensity (T1W/T2W ratio: rT1/T2) derived from conventional MRI could act as a surrogate relaxation time predictive of IDH mutation status in histologically lower-grade gliomas. Strong exponential correlations were found between rT1/T2 and each of T1- and T2-relaxation times in eight subjects (rT1/T2 = 1.63exp-0.0005T1-relax + 0.30 and rT1/T2 = 1.27exp-0.0081T2-relax + 0.48; R2 = 0.64 and 0.59, respectively). In a test cohort of 25 patients, mean rT1/T2 (mrT1/T2) was significantly higher in IDHwt tumors than in IDHmt tumors (p < 0.05) and the optimal cut-off of mrT1/T2 for discriminating IDHmt was 0.666-0.677, (AUC = 0.75, p < 0.05), which was validated in an external domestic cohort of 29 patients (AUC = 0.75, p = 0.02). However, this result was not validated in an external international cohort derived from TCIA/TCGA (AUC = 0.63, p = 0.08). The t-Distributed Stochastic Neighbor Embedding analysis revealed a greater diversity in image characteristics within the TCIA/TCGA cohort than in the two domestic cohorts. The failure of external validation in the TCIA/TCGA cohort could be attributed to its wider variety of original imaging characteristics.

Lymphoepithelioma-like cholangiocarcinoma not associated with Epstein-Barr virus or hepatitis virus: case report and literature review of 100 reported cases.

Lymphoepithelioma-like cholangiocarcinoma (LEL-CC) is a type of lymphoepithelioma-like carcinoma (LELC) and a rare variant of primary liver tumor. Although it is uncommon and only 100 cases have been reported thus far, the number of reports has increased in recent years. LEL-CC reportedly occurs more frequently in Asian women; Epstein-Barr virus (EBV) and hepatitis viruses are both strongly associated with tumor development. Here, we describe a 76-year-old woman who exhibited LEL-CC not associated with EBV or hepatitis virus. She was referred to our department with a 3.0-cm × 2.8-cm tumor in the left lobe of the liver. Based on computed tomography and magnetic resonance imaging findings, the tumor was preoperatively diagnosed as hepatocellular carcinoma. Thus, we performed extended left hepatectomy with caudal lobectomy. Histopathological examinations revealed columnar tumor cells with atypical nuclei that proliferated in a cord-like or glandular tubular pattern with dense lymphocytic infiltration. Immunohistochemical analysis showed negative HepPar-1 and arginase findings, indicating non-hepatocyte origin; however, the biliary-type cytokeratins CK7 and CK19 were detected. Based on these findings, the tumor was identified as LEL-CC. EBV-encoded RNA in situ hybridization findings were negative; the patient's clinical characteristics were not suggestive of hepatitis virus infection. In conclusion, we suggest that clinicians consider LEL-CC as a differential diagnosis for liver tumors in Asian women, including patients without EBV or hepatitis virus.

STAT1-mediated induction of Ly6c-expressing macrophages are involved in the pathogenesis of an acute colitis model.

BACKGROUND: The development of inflammatory bowel diseases is thought to be multifactorial, but the exact steps in pathogenesis are poorly understood. In this study, we investigated involvement of the activation of STAT1 signal pathway in the pathogenesis of an acute colitis model. METHODS: A dextran sulfate sodium-induced acute colitis model was established by using wild-type C57BL/6 mice and STAT1-deficient mice. Disease indicators such as body weight loss and clinical score, induction of cytokines, chemokines, and inflammatory cells were evaluated in the acute colitis model. RESULTS: Disease state was significantly improved in the acute colitis model using STAT1-deficient mice compared with wild-type mice. The induction of Ly6c-highly expressing cells in colorectal tissues was attenuated in STAT1-deficient mice. IL-6, CCL2, and CCR2 gene expressions in Ly6c-highly expressing cells accumulated in the inflamed colon tissues and were significantly higher than in Ly6c-intermediate-expressing cells, whereas TNF-α and IFN-α/ß gene expression was higher in Ly6c-intermediate-expressing cells. Blockade of CCR2-mediated signaling significantly reduced the disease state in the acute colitis model. CONCLUSIONS: Two different types of Ly6c-expressing macrophages are induced in the inflamed tissues through the IFN-α/ß-STAT1-mediated CCL2/CCR2 cascade and this is associated with the pathogenesis such as onset, exacerbation, and subsequent chronicity of acute colitis.

Severe immune checkpoint inhibitor-associated gastritis: A case series and literature review.

Background and study aims Recent advances in cancer treatment have involved the clinical application of immune checkpoint inhibitors (ICIs) for various type of cancers. The adverse events associated with ICIs are generally referred to as immune-related adverse events (irAEs). Gastrointestinal irAEs are a major disorder, but gastritis is not frequently observed. The aims of this study were to elucidate the clinical, endoscopic, and histological characteristics of irAE gastritis. Patients and methods Information on patients treated with ICIs were collected from a single institute over 3 years. IrAE gastritis was identified based on the clinical course and endoscopic and histopathological findings. Of the 359 patients treated with ICIs, four cases of irAE gastritis were identified in clinical records from the endoscopy unit. The endoscopic and histopathological findings were analyzed, and further immunohistochemical studies with immune subtype markers and programmed cell death ligand-1 (PD-L1) antibody were conducted. Results Among four patients with irAE gastritis, the remarkable endoscopic characteristics were network-pattern erosion, erythematous and edematous mucosa with thick purulent discharge, and fragile mucosa. Corresponding histological features were fibrinopurulent exudate, severe inflammatory cell infiltration, and epithalaxia, respectively. The PD-L1 expression rate was ≥ 1 % in the gastric tissue of all patients with gastritis. These patients were treated with prednisolone (PSL) and their symptoms improved within a few days to 2 weeks. Conclusions IrAE gastritis were characterized by specific endoscopic findings. The appropriate endoscopic diagnosis may lead to effective treatment with PSL.

IFN-α/ß-mediated NK2R expression is related to the malignancy of colon cancer cells.

Neurokinin 2 receptor (NK2R), a G protein-coupled receptor for neurokinin A (NKA), a tachykinin family member, regulates various physiological functions including pain response, relaxation of smooth muscle, dilation of blood vessels, and vascular permeability. However, the precise role and regulation of NK2R expression in cancer cells have not been fully elucidated. In this study, we found that high NK2R gene expression was correlated with the poor survival of colorectal cancer patients, and Interferon (IFN-α/ß) stimulation significantly enhanced NK2R gene expression level of colon cancer cells in a Janus kinas 1/2 (JAK 1/2)-dependent manner. NKA stimulation augmented viability/proliferation and phosphorylation of Extracellular-signal-regulated kinase 1/2 (ERK1/2) levels of IFN-α/ß-treated colon cancer cells and NK2R blockade by using a selective antagonist reduced the proliferation in vitro. Administration of an NK2R antagonist alone or combined with polyinosinic-polycytidylic acid, a synthetic analog of double-stranded RNA, to CT26-bearing mice significantly suppressed tumorigenesis. NK2R-overexpressing CT26 cells showed enhanced tumorigenesis and metastatic colonization in both lung and liver after the inoculation into mice. These findings indicate that IFN-α/ß-mediated NK2R expression is related to the malignancy of colon cancer cells, suggesting that NK2R blockade may be a promising strategy for colon cancers.

Novel rapid immunohistochemistry using an alternating current electric field identifies Rac and Cdc42 activation in human colon cancer FFPE tissues.

It is important to determine the activation status of Rac and Cdc42 in cancer tissues for the prediction of metastasis and patient prognosis. However, it has been impossible to detect their spatial activation on formalin-fixed paraffin embedded (FFPE) surgical specimens thus far. Here, we established a novel detection technique for activated Rac/Cdc42 in human colon cancer FFPE tissues by using a p21-activated kinase (PAK)-Rac binding domain (RBD) detection probe fused with glutathione S-transferase (GST), designated GST-PAK-RBD, and novel rapid-immunohistochemistry (R-IHC) systems using noncontact alterating-current electric field mixing, although there is a technical limitation in that it may not distinguish between Rac members and Cdc42. In 50 cases of colon cancer, various activation patterns of Rac/Cdc42 were observed, which were designated plasma membrane, cytoplasm, mixed pattern, and polarized distribution. The activity was striking in the invasive fronts of tumors and significantly correlated with tumor invasion properties evaluated by TNM classification. Of note, in tissue microarray (TMA) samples, 29 of 33 cases demonstrated higher Rac1/Cdc42 activity in the tumor area than the corresponding normal mucosa. In addition, positive correlations were detected between Rac/Cdc42 activity and clinicopathological factors such as venous and lymphatic vessel invasion. These results suggest that understanding Rac and Cdc42 activations in cancer tissues would be valuable as an option for molecular therapy as personalized medicine.