Analysis of c-kit Mutation of Gastrointestinal Stromal Tumors

PURPOSE: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumor, and express the KIT protein. Previous studies have reported KIT phosphorylation to be the principal biological event in the tumoriogenesis of GIST, which is generally evoked by the conformational mutation of KIT receptors. The aim of this study was to evaluate the frequency and category of c-kit mutations and their prognostic relevance. METHODS: The frequency and category of the c-kit mutations and the correlation between clinical outcome and the c-kit mutations were analyzed and the significance of the c-kit mutations examined as independent prognostic factors in 84 cases of GIST. The c-kit mutations were measured by polymerase chain reaction and DNA sequencing, using an ABI 3700 sequencer. RESULTS: c-kit mutations were noted in 14 of the 84 cases (16.7%) of GIST. Mutations in exon 11 were found in 11 cases (78.6%), exon 9 in 2 (14.3%) and exon 13 in 1 (7.1%), but no mutation was noted in exon 17. Of the mutations in exon 11, missense mutations were observed in 9 cases and frameshift mutations in 2. Among the 14 cases with c-kit mutations, 1 (7.1%) was found in a very low risk patient, 4 (28.6%) in intermediate risk patients and 9 (64.3%) in high risk patients. The c-kit mutations were observed more frequently in high risk patients (P=0.0366). However, there was no significant difference between the c-kit mutations and the survival rate. CONCLUSION: These results suggest that kit mutations might have a pathogenetic role in GIST, 550~560 in exon 11 of c-kit gene is the conserving area of mutation and c-kit mutations are uncertain as prognostic factors in GIST. However, further study will be required.

Analysis of c-kit Mutation of Gastrointestinal Stromal Tumors

PURPOSE: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumor, and express the KIT protein. Previous studies have reported KIT phosphorylation to be the principal biological event in the tumoriogenesis of GIST, which is generally evoked by the conformational mutation of KIT receptors. The aim of this study was to evaluate the frequency and category of c-kit mutations and their prognostic relevance. METHODS: The frequency and category of the c-kit mutations and the correlation between clinical outcome and the c-kit mutations were analyzed and the significance of the c-kit mutations examined as independent prognostic factors in 84 cases of GIST. The c-kit mutations were measured by polymerase chain reaction and DNA sequencing, using an ABI 3700 sequencer. RESULTS: c-kit mutations were noted in 14 of the 84 cases (16.7%) of GIST. Mutations in exon 11 were found in 11 cases (78.6%), exon 9 in 2 (14.3%) and exon 13 in 1 (7.1%), but no mutation was noted in exon 17. Of the mutations in exon 11, missense mutations were observed in 9 cases and frameshift mutations in 2. Among the 14 cases with c-kit mutations, 1 (7.1%) was found in a very low risk patient, 4 (28.6%) in intermediate risk patients and 9 (64.3%) in high risk patients. The c-kit mutations were observed more frequently in high risk patients (P=0.0366). However, there was no significant difference between the c-kit mutations and the survival rate. CONCLUSION: These results suggest that kit mutations might have a pathogenetic role in GIST, 550~560 in exon 11 of c-kit gene is the conserving area of mutation and c-kit mutations are uncertain as prognostic factors in GIST. However, further study will be required.

Treatment of Trichiasis and Districhiasis with Ellman Dento-Surg 90FFP

PURPOSE: To evaluate the efficacy of the Ellman Dento-Surg 90FFP for the isolated trichiasis or distichiasis. METHODS: 61 eyelashes of 23 patients, who were diagnosed as trichiasis or distichiasis and had less than 5 aberrant cilia that were isolated, were treated with the Ellman Dento-Surg 90FFP. At 1 week, 1 month, 2 month and 6 month postoperatively, we examined the success rate and postoperative complication. RESULTS: Fifteen eyelashes of 9 patients were regrown after mean 1.3month follow-up period (75.4% success rate). Among 10 eyelashes of 6 patients, 2 eyelashes of 2 patients were regrown (80% success rate). Thirteen patients experienced mild burning sensation 1-2 days postoperatively. Eyelid notching was observed in 2 patients. CONCLUSIONS: High frequency radio wave electrosurgery with Ellman Dento-Surg 90FFP is a simple and secure procedure with high success rate and negligible complication, and can be effectively used to treat isolated trichiasis or distichiasis.

Posterior Capsular Opacification and Nd: YAG Laser Capsulotomy in 811B, SI40NB, MA60BM Intraocular Lens

PURPOSE: To compare the incidence and the interval between the development of posterior capsular opacification (PCO) and Nd: YAG laser capsulotomy among patients implanted with a 811B, SI40NB, and MA60BM intraocular lens METHODS: One hundred ninty eyes of 157 patients who had undergone implant surgery with 811B, SI40NB, and MA60BM intraocular lens at the Presbyterian Medical Center were studied retrospectively. We compared the postoperative best corrected visual acuity, the incidence and the time interval between the development of PCO and laser capsulotomy, and the total energy used in laser capsulotomy among three intraocular lens groups. RESULTS: The incidence of development of PCO was 26.9% in 811B, 23.8% in SI40NB, and 10% in MA60BM groups, showing that incidence was significantly lower in the MA60BM group as compared to 811B (P=0.0016) or SI40NB (P=0.0056) group. The 811B group induced PCO earlier than SI40NB group. The energy used in Nd: YAG laser capsulotomy was lower in 811B than that in SI40NB or MA60BM. CONCLUSIONS: The incidence of posterior capsular opacification and that of Nd: YAG laser capsulotomy were found to be significantly lower in the MA60BM group than those in 811B or SI40NB group.

Repair of Scleral Ulcer with Bovine Pericardium

PURPOSE: This study was performed to evaluate the effect of bovine pericardium used in scleral ulcer resulting from excision of pterygium and MMC. METHODS: Nine eyes of 9 patients who had painful scleral ulcer resulting from excision of pterygium and MMC were repaired with bovine pericardium (Lyoplant(R)). The rotation conjunctival flap was placed over the graft area. We measured the results and complications of treatment. RESULTS: Eight patients showed loss of eyeball pain, epiphora, and inflammation. There were visual improvement, good conjunctival healing after the procedure. One patient showed loss of overlying conjunctiva and progression of scleral ulcer because of pseudomonas infection. After control of infection and secondary procedure, there were good conjunctival healing, relief of the symptom and visual improvement. CONCLUSIONS: The authors suggest bovine pericardium appears to be an excellent substitute for autogenous or homologous tissue in scleral ulcer treatment.

Two Cases of Endometrial Carcinoma in Tamoxifen-treated Breast Cancer Patients in Korea / 한국유방암학회지

Tamoxifen, the representative of selective estrogen receptor modulaor (SERM), has been widely used not only for the treatment of breast cancer, but also for the prevention of the disease. It is well known that some serious side-effects can infrequently occur with long-term use of tamoxifen and endometrial cancer is one of that disasters. According to NSABP B-14 data, the incidence of endometrial cancer among tamoxifen users was 0.16% and the relative risk was increased by 7.2 fold. In Korea, tamoxifen has been also used as primary endocrine therapy for the treatment of many patients with breast cancer. However, there was no formal report about the endometrial carcinoma occurred subsequently after tamoxifen administration so far. Recently, we experienced two cases of endometrial carcinoma occurred after tamoxifen treatment in breast cancer patients in Korea, and report these cases for reminding breast physicians or patients not to ignore this rare, but serious side effect of tamoxifen.

Two Cases of Combined Transplantation of Liver and Kidney from Two Living Donors / 대한이식학회지

Combined liver-kidney transplantation has gained increasing popularity and applied for the patient with end-stage liver and kidney disease. There are some controversies about the sequence of transplantation. In general, the liver allograft is temporary placed before the kidney allograft. This method may provide some immunologic advantages that liver allograft may protect concomitantly transplantated kidney from rejection. In our opinion, kidney-liver sequence may provide several benefits in hemodynamic stability, safer monitoring and planned fluid replacement by urine flow assessment. Combined liver-kidney transplantation requires only conventional immunosuppressive drug dosage as in kidney transplantation alone. And combined liver-kidney transplantation can be performed with acceptable morbidity and mortality, and have exellent long term result. We present two cases of combined liver-kidney transplantation performed by kidney- liver sequence for complex end organ failure.

Donor Safety in Living Donor Liver Transplantation Using Right Lobe / 대한이식학회지

PURPOSE: Right lobe donation is technically more difficult and need to define surgical technique and has more risk for surgical complication. Right lobe donation usually matched graft size but safety of donor is major concern. In this paper, we reviewed our experience of donor hepatectomy using right lobe in regarding to safe of our donor operations, retrospectively. METHODS: Retrospective analysis of 42 donor operations for adult LDLT using right lobe was performed. We observed the patient characteristics, the operative findings, peak liver enzymes (AST, ALT, bilirubin) as donor risk and mortality, morbidity. RESULTS: The peak value of liver enzymes in the group of less the 30% of remained liver were significantly higher than the group of more than 30% of remained liver and these values could induced the risk on donor. The postoperative peak value of liver enzymes were increased according to degree of fatty change especially in case of more than 10% fatty change even without significance. We observed the liver regeneration on postoperative 3 months and the regeneration of liver volume on postoperative 3 months was about two times compare to preoperative value and the regenerative activity was more increased in the group of less amount of remained volume. There was no donor mortality and most important complication was biliary complication, in which were biliary injury, bile leakage and biliary stricture. CONCLUSION: Right lobectomy for donor operation requires a meticulous surgical technique to minimize donor morbidity. Right lobectomy can be performed safely with minimal risk in case of careful donor selection that the remained liver volume exceed 30% of the total liver volume and the liver of minimal fatty change.

Prognostic Significance of Hormonal Receptors in Very Young Women with Early Breast Cancer / 한국유방암학회지

PURPOSE: The prognosis of breast cancer in very young women is generally considered to be unfavorable. In addition, younger patients (<35 years) with estrogen- receptor (ER) positive tumor had shown a significantly worse disease- free survival than younger patients with ER negative tumors. To confirm the prognostic effects of ER on the survival in very young Korean women with early breast cancer, we performed a retrospective study with survival analyses according to the expression of hormonal receptors. METHODS: Total 74 very young women with early breast cancer (invasive ductal carcinoma, NOS, < or=35 years, and stage

The Effect of Topical Mitomycin C after Excisional Biopsy in Conjunctival-corneal Intraepithelial Neoplasia: Two cases

PURPOSE: To investigate the effect of topical Mitomycin C(MMC) as a medical adjunct to incompletely excised conjunctival-corneal intraepithelial neoplasia(CCIN) for removal of remaining neoplastic cells and prevention of recurrence. METHODS: The authors applied postoperative topical 0.02% MMC adjunctively on 2 eyes of 2 patients with incompletely excised and histopathologically confirmed conjunctival-corneal intraepithelial neoplasia(CCIN) for 2weeks and if the lesion is not regressed, topical MMC treatment with the same regimen was added. RESULTS: Remaining lesions were completely regressed and no recurrence has been found with follow up to 25 months and 26 months in each case. CONCLUSIONS: Topical MMC chemotherapy would be an effective treatment modality on incompletely excised conjunctival-corneal intraepithelial neoplasia(CCIN) for removal of remaining neoplatic cells and prevention of recurrence.

The Effect of retinoic acid on the expression of cell adhesion molecules and binding to peritoneal mesothelium in gastric cancer cells

BACKGROUND: Peritoneal metastasis is one of the maj or types of the stomach cancer recurrence and the role of the adhesion molecules is thought to be very much important in this event. Retinoic acid (RA) has been known to induce the growth inhibition and differentiation of various malignancies, and apoptpsis and the change of expression of adhesion molecules have been reported to be involved in the action of RA. METHODS: We studied the adhesion abilities of SNU- 1, SNU-5, and SNU-6 cells to the peritoneal endothelial cells as well as the expression of the adhesion molecules (CD44, ICAM- 1) in Western blot analysis. And also we studied the expression of apoptosis and the change of expression patterns of the various isoforms of CD44 and the change of the adhsion abilities of the cell line cells after RA treatment. RESULTS: CD44 was expressed in SNU-5 and - 16, together with an isoform in SNU- 16. ICAM- 1 was not expressed in any of the cell line cells tested. After the treatment of RA in the concentration range of 1 - 5X10 - 5 M to three stomach cancer cell lines, growth inhibition, apoptosis and the change of expression of the CD44 were noted. After RA treatment , the expression of CD44H was weakly increased in SNU- 1, and was markedly increased in SNU-5. In SNU- 16, the expression of CD44H was decreased while that of CD44E were markedly increased. The adhesibility of cells to peritoneal cells was increased in relation with the increase of the CD44H expression, which shows the fact that the adhesibility of tumor cells to peritoneal mesothelial cells is mediated by CD44H recognizing hyaluronic acid. CONCLUSION: RA induces growth inhibition of stomach cancer cell line cells and increase the adhesiblity of stomach cancer cell line cells to peritoneal mesothelium. It is believed that RA decreases the metastatic ability of stomach cancer cells by upregulating the CD44H expression.

Bovine Pericardium as a Wrapping Material for Hydroxyapatite Orbital Implant

PURPOSE: To investigate the usefulness of a processed bovine pericardium(Lyoplant(R)) as a wrapping material for hydroxyapatite orbital implant. METHODS: The authors carried out hydroxyapatite orbital implantation with a processed bovine pericardium(Lyoplant(R)) as a wrapping material for hydroxyapatite sphere in 14 enucleation cases from October 1998 to May 2000, and evaluated postoperative complications, fibrovascular ingrowth and implant or prosthesis motility. RESULTS: Physical properties of bovine pericardium, such as tensile strength, flexibility, suture characteristics, were good. Complications were developed in 8 cases(5 eyes), but there was no serious complication such as an implant exposure. Fibrovascular ingrowth and implant or prosthesis motility were satisfactory. CONCLUSION: The authors suggest bovine pericardium(Lyoplant(R)) as an effective wrapping material for hydroxyapatite orbital implant.

Reoperation of Recurrent Gastric Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The aim of this study was to evaluate the outcome of reoperation in recurrent gastric cancers. MATERIALS AND METHODS: We conducted a retrospective analysis of 86 patients who underwent reoperation for recurrent gastric cancer. We reviewed the time interval between first operation and reoperation, as well as the recurrence pattern, type of reoperation, and survival following reoperation. RESULTS: the average time to reoperation following curative resection was 27.8+/-25.9 months (median 18.4 months). Fifty-three cases (61.6%) of reoperation were performed within 2 years follwoing the first operation. The most common reason for reoperation was intestinal obstruction followed by gastric remnant recurrence and intra-abdominal mass. Complete resection was possible in 14 cases (16.3%) and a palliative procedure such as partial resection or bypass procedures was performed in 54 cases. In 18 cases (20.9%), simple lapalotomy was done without any aid. The most common site of recurrence was the peritoneum followed by the gastric remnant, distant lymph node and hematogenous liver metastasis. Operative mortality was 10.5%. Excluding the 9 cases of operative mortality, the mean survival time after reoperation was 15.4+/-2.5 months (mean 8.6 months). Survival following complete resection was much longer than palliative procedure and exploration only (37.9+/-8.7 vs 10.9+/-1.5 vs 4.7+/-0.8 months, p=0.000) Conclusion : The complete resection of recurrent gastric cancer can prolong survival. Early detection of localized recurrence is important in order to increase the chance of complete resection.

Abdominopelvic Omentopexy to Prevent Postoperative Radiotherapy Complications in Rectal Cancer after Abdominoperineal Resection

PURPOSE: In rectal cancer, it is known that the postoperative radiotherapy is an effective way for reducing locoregional recurrence, especially if accompanied with concurrent chemotherapy. However, toxicity to small bowel was one of the major limitations to perform full-dose radiotherapy. For overcoming this problem, abdominopelvic omentopexy, which separates the small bowel from the pelvic cavity, was developed. This study analyses the acute and chronic complications related to the partitioning of the pelvic cavity and subsequent postoperative radiotheraphy. METHODS: From January 1990 to September 1999, medical records of 127 patients with rectal cancer who underwent abdominoperineal resection were retrospectively reviewed. Seventy-one of these patients belonged to stages B2 through D according to the modified Astler-Coller classification and underwent adjuvent chemoradiation therapy, and abdominopelvic omentopexy was performed in thirty- three patients. We compared postoperative radiotherapy complications between abdominopelvic omentopexy group and non-abdominopelvic omentopexy group. After abdominoperineal resection, the greater omentum covers whole small bowel like apron. The lateral edges are attached to both lateral peritoneal wall with continous running suture. The lower margin is sutured to the parietal peritoneum of the posterior abdominal wall at the level of the aortic bifurcation. The pelvic reperitonealization was carried out in whole patients. RESULTS: In the group of radiotheraphy with abdominopelvic omentopexy, six patients showed signs of acute radiation enteritis, whereas no case of chronic radiation- induced enteropathy was observed. Other complications were postoperative ileus (three patients), urinary problems (four patients), radiation dermatitis (ten patients), and radiation-induced leukopenia (three patients). In the group of radiotheraphy without abdominopelvic omentopexy, 7 out of 38 patient developed symptom and sign of radiation- induced chronic complication. The chronic complication rate is significantly lower in the omentopexy group than in the non-omentopexy group (P=0.0089). CONCLUSIONS: Abdominopelvic omentopexy is effective for preventing the late sequela of radiation-induced enteritis.

Risk Factors for Recurrence of Febrile Seizure in Children / 대한소아신경학회지

OBJECTIVE: We researched the factors influencing recurrence, frequency and recurrence interval after first attack of febrile seizure. METHODS: The study was performed in 125 children who visited emergency rooms and was followed up over 24 months after the first febrile seizure. Children were divided into several groups according to fever degree, onset age, sex, seizure duration, serum sodium concentration at first seizure attack. The recurrence rate, frequency, and recurrence interval of each group were then compared. RESULTS: 1) Febrile seizures recurred in 36(28.8%) of 125 children with 2.89 seizure episodes, and recurrence occurred within 6 months in 18(50.0%), within 12 months in 26(72.2%), within 18 months in 33(91.2%) after the first febrile seizures. 2) The recurrence rate was significantly high in children who developed seizures before 12 months of age(P<0.05), and slightly increased in cases with a positive family history and lower degree of fever groups, but statistically no significance was found. 3) Seizure frequencies were also high in younger age group(3.25 episodes), compared to the older age group. 4) Recurrence within 6 months from onset occurred in 72% of the young age group. The younger the age at first occurrence the more likely the recurrence rate. The duration of seizure, sex, and serum sodium concentration did not meaningfully affect recurrent rate and frequency. CONCLUSION: In children who have had a first febrile seizure, recurrence is common. The onset of the first febrile seizure at an early age was associated with an increased risk of more frequent recurrent febrile seizures and a short recurrence interval after first febrile seizure.

Complications of Hydroxyapatite Orbital Implants (A Review of 110 Consecutive Cases)

There are many clinical reports on implant exposure as a complication of hydroxyapatite orbital implantation, but relatively small number of reports have concerned full range of complications that can occur with hydroxyapatite orbital implants. The authors analyzed all the complications associated with the 110 hydroxyapatite orbital implants performed by one surgeon at the department of ophthalmology, Presbyterian Medical Center between January 1993 and June 1998, and discussed the management and progression of them. There were 8 kinds, 40 cases of soft tissue problems, 3 kinds, 20 cases of eyelid problems, and 7 kinds, 27 cases with prosthesis and pegging.Most of them were improved with conservative management and surgical treatments were required in 2 cases with conjunctival wound disruption, 5 cases with implant exposure, 3 cases with overgrowth of subconjunctival granulation tissue, 3 cases with ptosis, 1 case with eyelid laxity, 2 cases with peg extraction, and 4 cases with poor peg position. Surgeons and patients who want to use hydroxyapatite as an orbital implant would be more satisfied with thorough knowledge on many possible complications and their etiology, proper prevention and management.

Liver Transplantation for Hepatocellular Carcinomas

PURPOSE: Currently, the role of liver transplantation in the treatment of hepatocellular carcinomas with cirrhosis is controversial due to the shortage of donors and to the high recurrence rate after transplantation. What remain to be determined are the best treatment protocol and who are likely to have a good outcome after liver transplantation. METHODS: Eight patients (all male, range 30 to 67 years) with a hepatocellular carcinoma underwent liver transplantation between 1993 and 1999 in Catholic University, Medical College. The criteria for exclusion of transplantation were extrahepatic tumor metastasis, positive regional lymph nodes, and tumor thrombus on the main portal trunk. All except one were treated with preoperative arterial chemoembolization alone or combined with chemotherapy or ethanol injection. The follow-up period was from 5 months to 27 months. The pathologic findings, the recurrence, and the survival rate were analyzed. RESULTS: One patient had a tumor, larger than 5 cm in diameter (5.9 cm) and another patient had 6 nodules in number. Vascular invasion was present in 3 patients. Among the 8 patients, postsurgical TNM staging was stage III in 3 patients and stage IVA in 2 patients. During the follow-up, 7 of the 8 patients (87.5%) survived, and the number of disease-free survivals was 6 among the 8 patients (75%). One patient died with recurrent hepatitis C 6 months after transplantation without tumor recurrence. The patient who had the largest tumor in size had recurrent cancer on the abdominal wall at 9 months after transplantation, and subsequent pulmonary recurrences at 15 and 19 months which were treated by resection. CONCLUSION: Hepatocellular carcinoma could be a good indication for liver transplantation in selected patient, but the best protocol remains to be determined, especially in large tumors.

Sqamous Cell Carcinoma Arising from Hidradenitis Suppurativa

Hidradenitis suppurativa is a chronic inflammatory disease that originate in the apocrine glands of the skin, It results in fibrosis, sinus track formation, and scarring. Rarely it is complicated by squamous cell carcinoma arisihg from hidradenitis suppurativa were reported in the literature. We present a patient who suffered over 20 years from persistent, extensive hidradenitis suppurativa and who developed squamous cell carcinoma at the perianal area. During the 18 month follow-up period, no evidence of recurrence nor metastasis was found.

Detection of Micrometastasis in Lymph Nodes of Gastric Cancer Patients by CD44-Specific Reverse Transcriptase-Polymerase Chain Reaction

PURPOSE: Lymph-node metastasis is one of the most useful prognostic factors in patients with gastric carcinomas. However, micrometastatic carcinoma cells are frequently missed by conventional histo pathologic examination. Therefore, efforts have been made to detect micrometastasis in lymph nodes at the molecular level. In this study, we used a well-known stomach-cancer target molecule, a CD44 variant, to detect micrometastasis in lymph nodes. METHODS: The authors used the reverse transcriptase-polymerase chain reaction (RT-PCR) to detect tumour- specific splice variants of the transcript of the CD44 gene from 50 histologically metastasis negative lymph nodes in 11 gastric-cancer patients. Oligonucleotide primers as 5'-TCCAGACGAAGACAGT CCCGGAT-3' and 5'-CACTGGGGTGGAATGTGTCTTGGTC-3' were used. Southern blotting with a 40-mer oligonucleotide probe (5'-CCGACAGCACAGACAGAATCCCC- TGCTAC-3') corresponding to a sequence found in all known CD44 transcript isoforms was used to enhance the sensitivity. RESULTS: 1) CD44E could be detected at a concentration of as low as ten tumor cells per 104 peripheral blood lymphocytes in RT-PCR in serial 10-fold dilutions of SNU-16 gastric carcinoma cells with normal peripheral lymphocytes. Southern blotting enhanced the sensitivity to ten tumor cells per 106 peripheral blood lymphocytes. Normal blood did not show overexpression of CD44 splice variant. 2) Gel electrophoresis of reverse transcriptase-polymerase chain reaction products from histologically metastasis-negative lymph nodes of patients with stomach cancer identified a band of 479 base pairs corresponding to the CD44E form in 6 (12%) lymph nodes. 3) Southern blotting using a pan CD44 probe increased the sensitivity of the detection. Of the 50 lymph node samples, ten (20%) showed abnormal CD44 gene activity indicating the presence of micrometastasis. CONCLUSION: The findings of this study suggest that the CD44 RT-PCR/Southern blot hybridization is useful for the detection micrometastasis in lymph nodes. This method would be of practical value in selecting patients at high risk for relapse from those who have no histologically postitive lymph nodes.

Detection of Micrometastasis in Lymph Nodes of Gastric Cancer Patients by CD44-Specific Reverse Transcriptase-Polymerase Chain Reaction

PURPOSE: Lymph-node metastasis is one of the most useful prognostic factors in patients with gastric carcinomas. However, micrometastatic carcinoma cells are frequently missed by conventional histo pathologic examination. Therefore, efforts have been made to detect micrometastasis in lymph nodes at the molecular level. In this study, we used a well-known stomach-cancer target molecule, a CD44 variant, to detect micrometastasis in lymph nodes. METHODS: The authors used the reverse transcriptase-polymerase chain reaction (RT-PCR) to detect tumour- specific splice variants of the transcript of the CD44 gene from 50 histologically metastasis negative lymph nodes in 11 gastric-cancer patients. Oligonucleotide primers as 5'-TCCAGACGAAGACAGT CCCGGAT-3' and 5'-CACTGGGGTGGAATGTGTCTTGGTC-3' were used. Southern blotting with a 40-mer oligonucleotide probe (5'-CCGACAGCACAGACAGAATCCCC- TGCTAC-3') corresponding to a sequence found in all known CD44 transcript isoforms was used to enhance the sensitivity. RESULTS: 1) CD44E could be detected at a concentration of as low as ten tumor cells per 104 peripheral blood lymphocytes in RT-PCR in serial 10-fold dilutions of SNU-16 gastric carcinoma cells with normal peripheral lymphocytes. Southern blotting enhanced the sensitivity to ten tumor cells per 106 peripheral blood lymphocytes. Normal blood did not show overexpression of CD44 splice variant. 2) Gel electrophoresis of reverse transcriptase-polymerase chain reaction products from histologically metastasis-negative lymph nodes of patients with stomach cancer identified a band of 479 base pairs corresponding to the CD44E form in 6 (12%) lymph nodes. 3) Southern blotting using a pan CD44 probe increased the sensitivity of the detection. Of the 50 lymph node samples, ten (20%) showed abnormal CD44 gene activity indicating the presence of micrometastasis. CONCLUSION: The findings of this study suggest that the CD44 RT-PCR/Southern blot hybridization is useful for the detection micrometastasis in lymph nodes. This method would be of practical value in selecting patients at high risk for relapse from those who have no histologically postitive lymph nodes.