Cigarette Smoking Preferentially Affects Intracranial Vessels in Young Males: A Propensity-Score Matching Analysis / 신경중재치료의학

PURPOSE: Cigarette smoking (CS) is one of the major risk factors of cerebral atherosclerotic disease, however, its level of contribution to extracranial and intracranial atherosclerotic stenosis (ECAS and ICAS) was not fully revealed yet. The purpose of our study was to assess the association of CS to cerebral atherosclerosis along with other risk factors. MATERIALS AND METHODS: All consecutive patients who were angiographically confirmed with severe symptomatic cerebral atherosclerotic disease between January 2002 and December 2012 were included in this study. Multivariate logistic regression analyses were performed to identify risk factors for ECAS and ICAS. Thereafter, CS group were compared to non-CS group in the entire study population and in a propensity-score matched population with two different age-subgroups. RESULTS: Of 1709 enrolled patients, 794 (46.5%) had extracranial (EC) lesions and the other 915 (53.5%) had intracranial (IC) lesions. CS group had more EC lesions (55.8% vs. 35.3%, P<0.001) whereas young age group (<50 years) had more IC lesion (84.5% vs. 47.6%, P<0.001). In multivariate analysis, seven variables including CS, male, old age, coronary heart disease, higher erythrocyte sedimentation rate, multiple lesions, and anterior lesion were independently associated with ECAS. In the propensity-score matched CS group had significant more EC lesion compared to non-CS group (65.7% vs. 47.9%) only in the old age subgroup. CONCLUSION: In contrast to a significant association between CS and severe symptomatic ECAS shown in old population, young patients did not show this association and showed relatively higher preference of ICAS.

Is STONE score a useful tool for limiting the use computed tomography in the patients suspected ureter stone? - A single-center retrospective study

OBJECTIVE: The STONE score was developed to gauge the ureter stone probability. On the other hand, it is unclear if the STONE score is also applicable to Koreans. This study evaluated whether the STONE score can identify patients with suspected nephrolithiasis for whom a computed tomography (CT) scan can be obtained in the emergency department, targeting Koreans. METHODS: Patients presenting to the emergency medicine (ED) with flank pain and a suspicion of a ureter stone between January 2016 and December 2016 were reviewed retrospectively. After calculating the STONE score, the enrolled patients were classified into the low, moderate, high score group. In each group, the prevalence of a ureter stone and other clinical diseases on a CT scan were investigated. RESULTS: Among the 156 patients included in the analysis, 124 (79.5%) had a ureter stone and an alternative diagnosis was made in 12 (7.7%). The prevalence of a ureter stone and alternative diseases in the high score group was 87.7% (71/81) and 4.9% (4/81), respectively. The proportion of patients with nephrolithiasis increased significantly (P < 0.001), but the proportion of patients with other clinical diseases did not decrease significantly across the score groups (P=0.196). The area under the receiver operating characteristic curve was 0.711 (95% confidence interval, 0.633–0.780; P=0.001) with a cut off score higher than 8 (sensitivity 82.3%, specificity 50.0%) for the STONE score. CONCLUSION: In this setting, the STONE score had a low specificity and could not accurately assess a ureter stone. More studies aimed at Koreans are warranted before a CT scan can be limited using the STONE score.

Feasibility of the Transradial or the Transbrachial Approach in Various Neurointerventional Procedures / 신경중재치료의학

PURPOSE: The generally preferred vascular access for neurointerventional procedures is the transfemoral approach (TFA). In complicated cases such as patients with aortic diseases or tortuous vessels, transradial or transbrachial approaches (TRA or TBA) could be good alternatives. The purpose of this study is to review a single medical center experience using the alternative accesses. MATERIALS AND METHODS: We reviewed the medical records of 30 TRA and 10 TBA cases among 2,073 cases treated between January 2010 and July 2013. We reviewed and analyzed the frequency of TRA and TBA, the reason the operator had chosen the TRA or TBA, the category of the procedure, caliber of the sheath, the success rate, and the complications rates. RESULTS: The most common reason the non-TFA route was chosen was due to the patient's tortuous vascular system (n=24, 60%). The most common category of intervention was balloon angioplasty and/or stent placement (n=18, 45%). The largest caliber of the introducing sheath was 6 Fr in TRA and 7 Fr in TBA. Procedural success was achieved in 37 cases (success rate: 92.5%), and in three cases it failed. Six patients with complications were reported. Among them, four cases of minor complications (10%) occurred. There was no serious complication directly related to the access problem. CONCLUSION: Both TRA and TBA can be good alternative access routes when TFA is not appropriate in various neurointervential procedures.

Endovascular Management of Long-Segmental Petrocavernous Internal Carotid Artery (Carotid S) Occlusion / 대한뇌졸중학회지

BACKGROUND AND PURPOSE: Long-segmental thrombotic occlusion of the distal internal carotid artery (ICA) sparing the cervical segment proximally and the supraclinoid segment distally, which could be termed 'Carotid S occlusion', has an unusual clinical presentation. However, endovascular management of this lesion is challenging. The purpose of our study is to report our endovascular treatment clinical experience of the disease. METHODS: From March 2008 to June 2013, we could identify 14 patients (average age: 62.1, median age: 62, range: 50-79) with \'Carotid S occlusion', who underwent endovascular recanalization procedures. Patient's clinical presentations were collected and the imaging findings also analyzed. The technical success rate, 24-hour and follow-up imaging outcome, and the clinical outcome using the 90-day mRS (modified Rankin scale) score were evaluated. RESULTS: Patients presented with gradually progressing (n = 8), fluctuating (n = 3), transient ischemic attack (n = 2) and stationary (n = 1) symptoms. DWI showed internal and external border-zone lesions in six patients, only internal ICA border-zone lesions in three patients, and only external border-zone lesions in two patients. Underlying distal ICA stenosis was noted in 12 patients. The technical success rate was 92.8% (13/14). Luminal patency was noted in all patients (100%) after 24 hours and in nine of 10 (90%) on long-term follow-up (median: 6.5, average: 15.1, range: 1-39 months). A 90-day, good functional outcome (mRS < or = 2) was noted in 13 of 14 patients (92.8%). CONCLUSIONS: \'Carotid S occlusion' usually presented with border-zone infarction and endovascular management of the lesions was feasible. A relatively successful clinical outcome could be achieved after successful revascularization.

Mechanical Thrombectomy Using the Solitaire FR system for Occlusion of the Top of the Basilar Artery: Intentional Detachment of the Device after Partial Retrieval / 신경중재치료의학

Acute, distal, basilar artery occlusion is a challenging neurovascular emergency. There have been several reports regarding the successful application of the Solitaire FR device for treating this lesion. However, due to the lack of a suitable, balloon-tipped, guiding catheter for the vertebral artery, during this procedure we frequently experience the occurrence of clot fragmentation and distal migration. There may be some technical solutions to solve this problem. The purpose of this report is to present a technical variation of using the Solitaire FR, and which is referred to as the 'intentional device detachment technique.' As a clot tends to re-embolize during its passage through the tortuous cranio-cervical junction level of the vertebral artery or its passage through the tip of the guiding catheter, due to the lack of proximal flow arrest, we thought that not removing the stent segment of the device which is capturing the clot could avoid this problem. We were able to successfully apply this technique in two cases. We believe that this technique can be a possible technical option for using the Solitaire FR device when a patient has little concern regarding the subsequent use of antiplatelets.

Two Microcatheter Technique for Embolization of Arteriovenous Fistula with Liquid Embolic Agent / 신경중재치료의학

Problem with embolization of arteriovenous fistula (AVF) with liquid embolic agent is its over-penetration into the veins or regurgitation to the proximal feeder without reaching the shunt point. We present a technique that controls the flow of AVF during embolization. Two microcatheter technique consists of positioning one microcatheter close to the AVF for embolization, and with another microcatheter at the proximal feeding artery to control the AVF flow by coiling. Selective angiograms obtained using a distally positioned microcatheter before and after coiling, were compared how much stagnant effect was achieved. Using two microcatheter technique, AVF occlusion was achieved with good penetration of glue to the venous side of the AVF. Its advantage is the ability to push glue into the shunt without causing over-penetration of glue or its reflux along the feeder. Two microcatheter technique was safe and effective in glue embolization of AVF and also expected to be applied with other liquid embolic agent like Onyx.

A Study Design to Evaluate Association between Smoking and Intracranial Atherosclerotic Stenosis / 신경중재치료의학

PURPOSE: Smoking is a well known risk factor for stroke. The cerebral arteries may be uniquely susceptible to the atherosclerotic effects of smoking, such that it has a different risk profile for stroke compared with other atherosclerosis risk factors. It remains uncertain whether smoking is associated specifically with intracranial (IC) or extracranial (EC) atherosclerotic cerebrovascular disease. The aim of this study design will be to evaluate the association between smoking and severe IC stenosis, adjusting for other atherosclerosis risk factors, particularly age distribution. STUDY DESIGN: This is a retrospective cohort study design. Participants are patients (n=1714) with severe atherosclerotic stenosis undergoing cerebral catheter angiography because of stroke or transient ischaemic attack. All atherosclerotic steno-occlusive lesions are described in terms of location (anterior versus posterior circulation, IC versus EC, or intradural versus extradural). The atherosclerotic or stroke risk factors for analysis include age, gender, smoking history, number of lesions (single versus multiple), cardiac disease, diabetes mellitus, hypertension, family history, dyslipidemia, history of previous stroke, alcohol intake, metabolic syndrome and body mass index. Statistical analysis includes univariate analysis followed by multivariate logistic regression. The relationship between IC atherosclerotic stenosis and smoking will be assessed. Differences in risk factor distribution is analysed according to age at intervals of 10 years. Significant risk factors associated with IC atherosclerotic stenosis will also be assessed by multivariate logistic regression analysis. SUMMARY: This is an analytical study design that intends to measure the association between IC or EC atherosclerotic stenosis and smoking and other risk factors. We anticipate that it will have the power to detect any relationship between smoking and IC atherosclerotic lesions especially in younger patients.

Long-term Outcomes of Drug-eluting Stents in Symptomatic Intracranial Stenosis / 신경중재치료의학

PURPOSE: The use of drug-eluting stent (DES) to treat intracranial stenosis has shown short-term success. However, there are no reports regarding the long-term results of DES. We present the long-term clinical outcome after DES stenting for symptomatic severe intracranial stenosis. MATERIALS AND METHODS: Our study included a consecutive series of 11 patients who underwent intracranial stenting using DES between March and July, 2006, during the time when bare metal stents were not available at our medical institution. The mean patient age was 59 years. Lesion location was the middle cerebral artery in five patients, the intradural vertebral artery in three, the basilar artery in one, the vertebrobasilar junction in one, and the cavernous internal cerebral artery in one patient. We evaluated the technical success, defined as reduction of residual stenosis or =50% at during the mean follow-up period of 55 months. One patient died of a sudden heart attack 59 months following the procedure which was regarded as unrelated to the cerebral lesion. CONCLUSION: Our study demonstrates that DES shows long-term stability and safety, and results in good clinical outcomes with a low rate of restenosis.

Current Status of Neurointerventional Activities in Korea / 신경중재치료의학

Neurointervention which deals with neurovascular disease in brain, head-and-neck and spines are one of the rapidly evolving medical fields. Several indices representing neurointerventional activities are still increasing year-by-year in Korea. We review current trend in major neurovascular diseases requiring usage of specific medical devices and some issues related to administrative process of the government approval.

The Merits of Mannitol in the Repair of Orbital Blowout Fracture

BACKGROUND: One of the main concerns in orbital blowout fracture repair is a narrow operation field, due mainly to the innate complex three dimensions of the orbit; however, a deep location and extensive area of the fracture and soft tissue edema can also cause concern. Swelling of the orbital contents progresses as the operation continues. Mannitol has been used empirically in glaucoma, cerebral hemorrhage, and orbital compartment syndrome for decompression. The authors adopted mannitol for the control of intraorbital edema and pressure in orbital blowout fracture repair. METHODS: This prospective study included 108 consecutive patients who were treated for a pure blowout fracture from January 2007 to October 2012. For group I, mannitol was administered during the operation. Under general anesthesia, all patients underwent surgery by open reduction and insertion of an absorbable mesh implant. The authors compared postoperative complications, the reoperation rate, operation time, and surgical field improvement between the two groups. RESULTS: In patients who received intraoperative administration of mannitol, the reoperation rate and operation time were decreased; however, the difference was not statistically significant. The total postoperative complication rates did not differ. Panel assessment for the intraoperative surgical field video recordings showed significantly improved vision in group I. CONCLUSIONS: For six years, mannitol proved itself an effective, reliable, and safe adjunctive drug in the repair of orbital blowout fractures. With its rapid onset and short duration of action, mannitol could be one of the best methods for obtaining a wider surgical field in blowout fracture defects.

Expression of Cortactin and Focal Adhesion Kinase in Colorectal Adenocarcinoma: Correlation with Clinicopathologic Parameters and Their Prognostic Implication

BACKGROUND: Cortactin and focal adhesion kinase (FAK) are two important components among actin cross-linking proteins that play a central role in cell migration. METHODS: The aims of this study were to evaluate the expression of cortactin and FAK in normal colorectal mucosa and colorectal adenocarcinoma (CRC) using tissue microarray of 2 mm cores to correlate their expression with other clinicopathological factors and, investigate their prognostic significance. RESULTS: Twenty (9%) and 24 cases (11%) of normal colorectal mucosa were immunoreactive for cortactin and FAK. In addition, 184 (84%) and 133 cases (61%) of CRCs were immunoreactive for cortactin and FAK, respectively. Cortactin expression was associated with histologic differentiation and FAK expression. Cortactin, but not FAK expression was also correlated with poor overall and relapse-free survival and served well as an independent prognostic factor for poor survival. CONCLUSIONS: Cortactin expression, in association with FAK expression, may plays an important role in tumor progression. Furthermore, it may also be a satisfactory biomarker to predict tumor progression and survival in CRC patients.

Expression of CHOP in Squamous Tumor of the Uterine Cervix

BACKGROUND: High-risk human papillomavirus (HR-HPV) infection and abnormal p53 expression are closely involved in carcinogenesis of squamous cell carcinoma (SqCC) of uterine cervix. Recent studies have suggested that virus-induced endoplasmic reticulum (ER) stress modulates various cell survival and cell death signaling pathways. The C/EBP homologous protein (CHOP) is associated with ER stress-mediated apoptosis and is also involved in carcinogenesis of several human cancers. We hypothesized that CHOP is involved in the carcinogenesis of uterine cervical cancer in association with HR-HPV and/or p53. METHODS: Immunohistochemistry was used to analyze CHOP and p53 protein expression of tissue sections from 191 patients with invasive cancer or preinvasive lesions of the uterine cervix (61 cases of SqCC, 66 cases of cervical intraepithelial neoplasia [CIN] III, and 64 cases of CIN I). RESULTS: CHOP was expressed in 59.4% of CIN I, 48.5% of CIN III, and 70.5% of SqCC cases. It was also significantly more frequent in invasive SqCC than in preinvasive lesions (p=0.042). Moreover, CHOP expression significantly correlated with HR-HPV infection and p53 expression (p=0.009 and p=0.038, respectively). CONCLUSIONS: Our results suggest that CHOP is involved in the carcinogenesis of the uterine cervix SqCC via association with HR-HPV and p53.

Fine Needle Aspiration Cytology of Metastatic Adenocarcinoma of the Gingiva from the Lung: A Case Report

Metastases of malignant tumors to the oral region from distant sites are uncommon. A 45-year-old man with painless gingival swelling was diagnosed with adenocarcinoma of the lung. On cytology, clusters of tumor cells on mucous background revealed enlarged nuclei, indistinct cell borders, and irregular nuclear membranes. Some cells showed nuclear inclusions, nuclear grooves and small nucleoli. These findings are indicative of metastatic adenocarcinoma. We present a case of gingival metastasis from a lung adenocarcinoma.

Application of Mini-abdominoplasty after Conservative Excision of Extensive Cesarean Scar Endometriosis

Endometriosis is defined as the presence of functioning endometrial tissue outside the uterine cavity, and the standard treatment is extensive surgical excision. Cesarean scar endometriosis is a type of cutaneous endometriosis arising on or near a Cesarean section scar. A 44-year-old woman presented with a 9x6 cm sized dark-brown, stony-hard, irregular, lower abdominal mass of four years duration. The patient had a history of two Cesarean deliveries, 14 and 16 years ago. Suspecting endometriosis, we excised the tumor conservatively rather than extensively to prevent incisional hernia considering the benign nature of the tumor and the low possibility of recurrence because the patient's age was near menopause, along with simultaneous bilateral salpingo-oophorectomy that was performed in this case. On reconstruction, mini-abdominoplasty was adopted to avoid possible wound complications and cosmetic deformities. The patient was satisfied with the cosmetic results, and neither recurrence nor functional problems occurred during the 1-year follow-up period. Plastic surgeons should keep in mind the possibility of cutaneous endometriosis in an abdominal mass of a female of reproductive age with a previous history of pelvic or intra-abdominal surgery. An optimal result from oncological, functional, and cosmetic standpoints can be achieved with conservative excision followed by mini-abdominoplasty of extensive Cesarean scar endometriosis.

Expressions of E-cadherin, Cortactin and MMP-9 in Pseudoepitheliomatous Hyperplasia and Squamous Cell Carcinoma of the Head and Neck: Their Relationships with Clinicopathologic Factors and Prognostic Implication

BACKGROUND: E-cadherin, cortactin, and matrix metalloproteinase (MMP)-9 have roles in tumor development or progression, but their expression has not been fully investigated in pseudoepitheliomatous hyperplasia (PEH) and squamous cell carcinoma (SCC) of the head and neck. METHODS: We evaluated the immunohistochemical expression of E-cadherin, cortactin, and MMP-9 in 29 cases of PEH and 97 cases of SCC. Additionally, we evaluated their relationship with clinicopathologic factors and prognostic implications in SCC. RESULTS: Thirty-five cases of SCC showed reduced expression of E-cadherin, whereas none of the PEH did. A total of 20 cases and 11 cases of SCC were immunoreactive for cortactin and MMP-9, respectively, whereas none of the PEH did. In SCC, reduced expression of E-cadherin was correlated with cortactin expression and invasion depth. Cortactin expression was correlated with differentiation, T classification, and recurrence and/or metastasis. MMP-9 expression was correlated with invasion depth. Cortactin expression was correlated with poor overall survival and relapse-free survival and it was an independent prognostic factor. CONCLUSIONS: The reduced expression of E-cadherin and the expression of cortactin may be helpful for the differential diagnosis of PEH and SCC. Furthermore, cortactin expression in association with reduced E-cadherin expression is correlated with poor prognosis in SCC.

Squamous Cell Carcinoma and Basal Cell Carcinoma Simultaneously Arising in a Nevus Sebaceus: A Case Report

PURPOSE: Nevus sebaceus is a congenital hamartomatous lesion, typically involving head and neck. Various benign and malignant neoplasms can develop in association with nevus sebaceus. We report a case of simultaneous occurrence of squamous cell carcinoma and basal cell carcinoma in nevus sebaceus. METHODS: A 73-year-old man presented with erythematous to black verrucous nodules on the right subauricular area. The upper part was accompanied with inflammation and ulceration, and no specific findings suspicious for malignant degeneration were found in the lower part preoperatively. The mass was totally excised and the defect was directly closed. Lymph nodes were not involved on concomitant neck dissection. RESULTS: Histopathologic examination confirmed the presence of squamous cell carcinoma in the upper part and basal cell carcinoma in the lower part of a nevus sebaceus. Negative margins were achieved on resection. No clinical problems were found during the 3-month follow-up period. CONCLUSION: We experienced a rare case of simultaneous occurrence of squamous cell carcinoma and basal cell carcinoma within the same nevus sebaceus. Because patients with nevus sebaceus have risk of malignant changes, surgical excision and work-up for recurrence and metastasis should be considered in suspicious cases. And even in a totally asymptomatic case, the possibility of occult secondary cancer should be informed before surgery in aged patients.

Concurrent Large Cell Neuroendocrine Carcinoma and Adenocarcinoma of the Ascending Colon: A Case Report

Large cell neuroendocrine carcinomas of the colon are rare and represent only a small percentage of all colonic endocrine tumors. Here, we report a case of a colonic large cell neuroendocrine carcinomas concurrent with a colonic adenocarcinoma. A 70-year-old man presented with acute abdominal pain. A spiral computed tomography scan of the abdomen revealed eccentric wall thickening on the ascending colon. An explorative laparotomy and a right hemicolectomy were performed. Grossly, two separated masses were observed in the proximal ascending colon. One was a 7.4 x 5.1 cm ulcerative fungating lesion, and the other was a 2.8 x 1.9 cm polypoid lesion. Microscopically, the ulcerative fungating lesion showed a well-differentiated neuroendocrine morphology with necrosis and increased mitosis. Most of the tumor cells had large, vesicular nuclei with eosinophilic nucleoli, variable amounts of eosinophilic cytoplasm, and immunoreactivity for chromogranin A and synaptophysin. The polypoid lesion was a well-differentiated adenocarcinoma that had invaded the submucosa. We diagnosed these lesions as a concurrent large cell neuroendocrine carcinoma and an adenocarcinoma of the ascending colon.

Characterization of a Novel Monoclonal Antibody (27H2) Recognizing Human CD34 Class III Epitope

BACKGROUND: Monoclonal antibodies (mAbs) recognizing Class III epitope of CD34 are essential for flow cytometric diagnosis of leukemia. METHODS: 27H2 mAb was developed from a mouse alternatively immunized with human acute leukemia cell lines, KG1 and Molm-1. Using flow cytometric analysis of various leukemic cell lines and peripheral blood, immunohistochemical study of frozen tonsil, we characterized 27H2 mAb. Antigen immunoprecipitated with 27H2 mAb immunobloted with anti-CD34 mAb. A case of bone marrow sample of acute lymphoblastic leukemia (ALL) patient was obtained at CBNU Hospital. For epitope identification enzyme treatment with neuraminidase and O-sialoglycoprotein endopeptidase (OSGE) and blocking assay with known classIII mAb (HPCA-2) were done. RESULTS: Only KG1 and Molm-1 revealed positive immunoreactivity. Immunohistochemical staining disclosed strong membranous immunoreactivity on high endothelial venules. Antigen immunoprecipitated by 27H2 mAb showed approximately 100 kDa sized band immunoblotted with anti-CD34 under non-reducing conditions. Epitope recognized by 27H2 mAb disclosed resistancy to both neuraminidase and OSGE treatment and completely blocked with known class III mAb preincubation. CD34 positive leukemic cells in BM of pre B cell ALL patient detected by FITC-conjugated 27H2 and HPCA-2 were identified with similar sensitivity. CONCLUSION: A novel murine mAb recognizing class III epitope of human CD34 with high affinity, which is useful for flow cytometric diagnosis of leukemia, was developed.

Antipsychotic Effects of Quetiapine in Naturalistic Long Term Follow Up Study

OBJECTIVE: This study aimed to examine the effectiveness of quetiapine and the effects of dosage relates to its effectiveness on schizophrenia and schizoaffective disorder in a naturalistic setting in Korean people. METHODS: This study was a 24-week, open-label, non-comparative, naturalistic study of quetiapine in patients diagnosed with schizophrenia and schizoaffective disorder according to DSM-IV. We stratified the patients into mild [(clinical global impression severity (CGI-S) or =4 at baseline). We investigated the response rate, defined as clinical global impression improvement (CGI-I) < or =2, in the severe group and the aggravation rate in the mild group using the last-observation-carried-forward (LOCF) and the Kaplan-Meier method (K-M). RESULTS: During the 24 weeks, 151 (18.4%) of the participants dropped out of the study. There was a significant decrease in the mean CGI-S score, from 4.5+/-1.1 at baseline to 2.8+/-1.1 at 24 weeks. The response rate of severe group was 54.5% (estimated by LOCF) and 73.3% (K-M estimated) at 24 weeks. All patients who completed the study had taken a mean quetiapine dosage of 507.9+/-245.9 mg daily. The decrease of CGI-S score in high-dose group (the maximum dose was 750 mg/d or above) was statistically significant than that in recommended-dose group (the maximum dose was less than 750 mg/d). CONCLUSION: This study demonstrated the long-term effectiveness of quetiapine in the treatment of schizophrenia and schizoaffective disorder in a naturalistic setting in Korean people. This study suggests that higher than recommended quetiapine dosages could be more effective in some patients.

Effects of Delay in the Snap Freezing of Colorectal Cancer Tissues on the Quality of DNA and RNA

PURPOSE: The success of basic molecular research using biospecimens strongly depends on the quality of the specimen. In this study, we evaluated the effects of delayed freezing time on the stability of DNA and RNA in fresh frozen tissue from patients with colorectal cancer. METHODS: Tissues were frozen at 10, 30, 60, and 90 minutes after extirpation of colorectal cancer in 20 cases. Absorbance ratio of 260 to 280 nm (A(260)/A(280)) and agarose gel electrophoresis were evaluated. In addition, the RNA integrity number (RIN) was assayed for the analysis of the RNA integrity. RESULTS: Regardless of delayed freezing time, all DNA and RNA samples revealed A(260)/A(280) ratios of more than 1.9, and all DNA samples showed a discrete, high-molecular-weight band on agarose gel electrophoresis. The RINs were 7.53 +/- 2.04, 6.70 +/- 1.88, 6.47 +/- 2.58, and 4.22 +/- 2.34 at 10, 30, 60, and 90 minutes, respectively. Though the concentration of RNA was not affected by delayed freezing, the RNA integrity was decreased with increasing delayed freezing time. CONCLUSION: According to the RIN results, we recommend that the collection of colorectal cancer tissue should be done within 10 minutes for studies requiring RNA of high quality and within 30 minutes for usual RNA studies.