Comparative detection of lymph node micrometastases of stage II colorectal cancer by reverse transcriptase polymerase chain reaction and immunohistochemistry

Detection of lymph node micrometastasis in gastric cancer by MUC2 RT-PCR: usefulness in pT1 cases

BACKGROUND AND OBJECTIVES

The objectives of this study were to evaluate the clinical utility of MUC2-specific reverse transcriptase-polymerase chain reaction (RT-PCR) in gastric cancer patients and to compare MUC2-specific RT-PCR to carcinoembryonic antigen (CEA)-specific RT-PCR.

METHODS

A total of 305 lymph nodes from 28 patients with gastric cancer were histologically examined and analyzed by MUC2 RT-PCR and CEA RT-PCR.

RESULTS

MUC2 and CEA were expressed in 17.1 and 7.0% of the 286 histologically negative lymph nodes, respectively. The detection rate of MUC2 was significantly higher than that of CEA (P < 0.01). MUC2 RT-PCR revealed no false positive results in control specimens. Lymph node micrometastases in pT1 gastric cancer were expressed only in perigastric lymph nodes near the tumor and were not detected in tumor less than 30 mm in patients with mucosal cancer.

CONCLUSIONS

MUC2-specific RT-PCR is a sensitive and specific method to detect lymph node micrometastases in gastric cancer patients. The distribution of lymph node micrometastases detected by this method may be useful in minimally invasive procedures for gastric cancer, especially pT1 cases.

Tumor micrometastases in mesorectal lymph nodes and their clinical significance in patients with rectal caner

AIM: To investigate the number, size, and status of lymph nodes within the mesorectum and to explore the prognostic significance of lymph node micrometastases in patients with rectal cancer.

METHODS: Thirty-one patients with rectal cancer undergone total mesorectal excision between October 2001 and October 2002 were included. Mesorectal nodes retrieved from the resected specimens were detected with a combination of haematoxylin and eosin (HE) staining and immunohistoch-emistry (IHC). The relations between lymph node metastases, micrometastases and postoperative recurrence were analyzed.

RESULTS: A total of 548 lymph nodes were harvested, with 17.7 ± 8.2 nodes per case. The average number of metastatic nodes in HE-positive patients and micrometastatic nodes in IHC-positive patients was 5.2 ± 5.1 per case and 2.2 ± 1.3 per case, respectively. The mean size of all nodes and metastatic nodes was 4.1 ± 1.8 mm and 5.2 ± 1.7 mm in diameter, respectively. The mean size of micrometastatic nodes was 3.9 ± 1.4 mm in diameter. The size of the majority of mesorectal nodes (66.8%), metastatic nodes (52.6%), and micrometastatic nodes (79.5%) was less than 5 mm in diameter. During a median follow-up period of 24.6 ± 4.7 mo, 5 patients (16.7%) had recurrence, of them 2 died and 3 survived. Another case died of tumor unrelated cause and was excluded. All 5 recurrent cases had 3 or more nodes involved, and one of them developed only lymph node micrometastases. The mean number of both metastatic and micrometastatic nodes per case differed significantly between the recurrent and non-recurrent groups (P < 0.01 and P = 0.01, respectively).

CONCLUSION: The majority of lymph nodes, metastatic, and micrometastatic lymph nodes within the mesorectum are smaller than 5 mm in diameter. The nodal status and the number of lymph nodes involved with tumor metastases and micrometastases are related to the rapid postoperative recurrence.

Risk factors for an adverse outcome in early invasive colorectal carcinoma

BACKGROUND & AIMS

Various histologic findings exist for managing patients with malignant polyps. Our goal was to determine the criteria for a conservative approach to patients with locally excised early invasive carcinoma.

METHODS

In 292 early invasive tumors (local resection followed by laparotomy [80 tumors, group A], local resection only [41 tumors, group B], and primarily laparotomy [171 tumors, group C], potential parameters for nodal involvement were analyzed. The status of the endoscopic resection margin also was examined for the risk for intramural residual tumor.

RESULTS

Unfavorable tumor grade, definite vascular invasion, and tumor budding were the combination of qualitative factors that most effectively discriminated the risk for nodal involvement in patients in groups A-C. The nodal involvement rate was 0.7%, 20.7%, and 36.4% in the no-risk, single-risk, and multiple-risks group, respectively. Thirty-two and 9 patients from group B were assigned to the no-risk and one-risk group, respectively; extramural recurrence occurred in 2 patients with risk factors. Considering quantitative risk parameters for submucosal invasion (i.e., width > or =4000 microm or depth > or =2000 microm), nodal involvement (including micrometastases) was not observed in the redefined no-risk group that accounted for about 25% of the patients from groups A and C. An insufficiency of endoscopic resection could be evaluated most precisely based on the coagulation-involving tumor, rather than the 1-mm rule for the resection margin.

CONCLUSIONS

Provided that the criterion of sufficient excision is satisfied, the absence of an unfavorable tumor grade, vascular invasion, tumor budding, and extensive submucosal invasion would be the strict criteria for a wait-and-see policy.

Gene Expression Profiles and Molecular Markers To Predict Recurrence of Dukes' B Colon Cancer

Purpose

The 5-year survival rate of patients with Dukes' B colon cancer is approximately 75%. Identification of the patients at high risk of recurrence in this group would allow better staging and more informed use of adjuvant chemotherapy. In this study, we used DNA chip technology to systematically identify new prognostic markers for tumor relapse in Dukes' B patients.

Patients and Methods

Using Affymetrix U133a GeneChip containing approximately 22,000 transcripts (Affymetrix, Santa Clara, CA), RNA samples from 74 patients with Dukes' B colon cancer were analyzed. Thirty-one patients developed tumor relapse in less than 3 years, whereas 43 patients remained disease-free for more than 3 years after surgery. Two supervised class prediction approaches were used to identify gene markers that can best discriminate between patients who would experience relapse and patients who would remain disease-free. A multivariate Cox model was built to predict recurrence.

Results

Gene expression profiling identified a 23-gene signature that predicts recurrence in Dukes'B patients. This signature was validated in 36 independent patients. The overall performance accuracy was 78%. Thirteen of 18 relapse patients and 15 of 18 disease-free patients were predicted correctly, giving an odds ratio of 13 (95% CI, 2.6 to 65; P = .003). The log-rank test indicated a significant difference in disease-free time between the predicted relapse and disease-free patients (P = .0001).

Conclusion

The clinical value of these markers is that the patients at a high predicted risk of relapse (13-fold risk) could be upstaged to receive adjuvant therapy, similar to Dukes' C patients. Our data highlight the feasibility of a prognostic assay that could focus more intensive treatment for localized colon cancer.

Application of molecular diagnosis for detection of peritoneal micrometastasis and evaluation of preoperative chemotherapy in advanced gastric carcinoma

BACKGROUND

In advanced gastric cancer, peritoneal recurrence is the main cause of death after curative surgical resection. The aim of this report was to describe a novel approach for quantitative genetic diagnosis using peritoneal lavage for the identification of patients at high risk for peritoneal recurrence and for evaluation of the clinical response to intraperitoneal chemotherapy in advanced gastric cancer.

METHODS

Nineteen patients with advanced gastric cancer who underwent staging laparoscopy and intraperitoneal chemotherapy before surgical resection or systemic chemotherapy between June 1999 and September 2001 were enrolled in this study. All peritoneal lavage specimens, collected at both staging laparoscopy and gastrectomy, were subjected to real-time quantitative genetic diagnosis.

RESULTS

The reverse transcriptase polymerase chain reaction (RT-PCR) values decreased in 8 cases, stabilized as negative in 5, and increased in 6 during therapy. Patients whose RT-PCR values diminished and were ultimately negative survived except for one, and all but one patient whose values increased during treatment died of recurrence.

CONCLUSIONS

Quantitative evaluation of genetic changes can provide accurate, useful information on the effects of preoperative intra-abdominal chemotherapy and overall prognosis for patients with advanced gastric cancer.

Immunohistochemical Studies in the Identification of Lymph Node Micrometastases in Patients with Squamous Cell Carcinoma of the Head and Neck

In the prediction of likely disease-free and overall survival intervals in patients with squamous carcinomas of the head and neck, cervical lymph node status assumes a prime role, and patients with cervical node metastases have diminished survivals, as a group, compared with patients whose cervical nodes are reported as negative for metastatic carcinoma. Conventional means of pathologic examination of cervical node biopsy specimens include examination of a single section through each individual node identified on gross examination, a process which, of necessity, leaves a significant portion of the node unexamined by microscopy. Recently, it has become apparent that more exhaustive pathologic sampling techniques, such as examining multiple sections of each lymph node, or staining each lymph node with antibodies to keratin via immunohistochemistry, will reliably yield a greater incidence of positive cervical lymph nodes ("micrometastases") than do conventional pathologic techniques. This suggests that the next line of inquiry should answer this question: just because micrometastases can be detected, should they be? Does the identification of (otherwise likely to be overlooked) tiny microscopic foci of spread of tumor in regional nodes by more sophisticated techniques yield additional data of real import to the patients, or is such information of lesser value? Should a role be defined in the care of head and neck cancer patients for the use of such advanced inquiries in the structuring of therapies, then the best approach to finding such elusive micrometastases (intraoperative immunohistochemistry? immunohistochemistry using routinely fixed tissues? polymerase chain reaction?) may subsequently be established.

Jaundice secondary to isolated porta hepatis metastasis in colorectal cancer: case report and review of the literature

Colorectal cancer occurs mainly after the age of 50. The liver is the most frequent site of metastases, although isolated metastases to the porta hepatis are rarely reported in the literature. From 1924 to 1993, only 16 cases of periportal lymph nodes metastases were reported. We report a case of jaundice secondary to porta hepatis metastases from primary colorectal cancer. The appearance of symptoms was concurrent with the elevation of carcinoembryonic antigen in our case. This emphasizes the importance of polymerase chain reaction to detect the small amount of carcinoembryonic antigen transcript in blood or in peritoneal fluid before the appearance of symptoms. Polymerase chain reaction allows the prediction of high risk of recurrence and the presence of micrometastases. More trials are needed to assess the outcome after treatment by adjuvant chemotherapy for micrometastases.

Minimal residual disease assessment in sentinel nodes of breast and gastrointestinal cancer: a plea for standardization

Lymph node dissection plays an important role in staging and treatment of solid cancers. Sentinel node biopsy (SNB) has been introduced to minimize the extent of surgery and to enable assessment of minimal residual disease (MRD) without compromising accurate staging or survival. This review addresses the variation in technical aspects and outcome of SNB and MRD assessment in patients with breast and gastrointestinal cancer. Quality control leading to standardization of SNB and pathological examination will enable reliable comparison of studies, which is necessary for consensus of diagnostic and therapeutic strategies.

Hepatic expression of ANG2 RNA in metastatic colorectal cancer

We examined the RNA content of the gene encoding angiopoietin (Ang)-2, a modifier of angiogenesis, in hepatic metastases of colorectal cancer (CRC) to explore the role of this protein in neovascularization of metastatic foci. Metastatic CRC exhibited notable blood flow and tumor vessel formation at tumor frontiers. Reverse-transcription polymerase chain reaction assays indicated that the ANG2 RNA content was greater in metastatic CRC than in primary CRC. Investigation of metastatic foci using laser capture microdissection revealed that the RNA content of ANG2, but not ANG1, increased from the bordering liver region to the periphery of the metastatic disease, and also from the periphery to the intermediate portion of the metastatic lesion; immunohistochemical analysis confirmed that there was a corresponding gradual increase in Ang-2 protein expression. Tie-2, a receptor for angiopoietins, was preferentially expressed in the bordering liver region rather than in metastatic CRC. Vascular endothelial growth factor (VEGF) also exhibited an expression pattern similar to that of Ang-2, and there was a significant correlation between the RNA content of ANG2 and that of VEGF in dissected samples (P =.002). Western blot analysis suggested that expression of Ang-1, Ang-2, Tie-2, and VEGF may be regulated at a transcriptional level. The increase in ANG2 RNA content from the peripheral portion of the tumor to the intermediate portion, coinciding with the decrease in recruitment of periendothelial supporting cells around the vascular endothelial cells, suggests that Ang-2 may play a role in the immaturity of tumor vessels. In conclusion, the current study suggests that Ang-2 and VEGF may cooperate to enhance the formation of new blood vessels in metastases of CRC to the liver.

Prediction of disease outcome in melanoma patients by molecular analysis of paraffin-embedded sentinel lymph nodes

PURPOSE

A significant number of patients who develop recurrence after a histopathologically negative sentinel lymph node (SLN) biopsy will demonstrate occult metastases on re-evaluation of the SLNs with serial sectioning and immunohistochemistry. Reverse transcriptase polymerase chain reaction (RT-PCR) has been evaluated to improve disease staging and avoid false-negative findings in fresh or frozen-section SLNs. The purpose of this study was to develop a multimarker RT-PCR assay for assessing melanoma patients' archived paraffin-embedded (PE) SLNs.

PATIENTS AND METHODS

Archived PE histopathologically positive (n = 37) and negative (n = 40) SLNs from patients with primary melanoma were analyzed using a semiquantitative multimarker RT-PCR assay.

RESULTS

Marker expression in histopathologically positive and negative SLNs were as follows: 89%, 92%, 35%, and 43% (positive) and 40%, 33%, 5%, and 13% (negative) for tyrosinase, melanoma antigen recognized by T cells-1, tyrosinase-related protein-1, and tyrosinase-related protein-2, respectively. Twenty-five percent of histopathologically negative SLN patients were upstaged using at least two markers. Of these, 80% developed a recurrence. Furthermore, at a median follow-up of 55 months, patients with histopathologically negative SLNs who expressed zero or one marker had a significantly improved disease-free (P <.002) and overall (P <.03) survival versus those expressing two or more markers.

CONCLUSION

These findings demonstrate the feasibility of a multimarker RT-PCR assay for evaluating archived PE SLNs. More significantly, identification of molecular risk factors can be detected in histopathologically negative SLNs for distinguishing early-stage melanoma patients with a worse prognosis.

Micrometastases in sentinel nodes of gastric cancer

The sentinel node (SN) is the first lymph node in the lymphatic basin to be affected by metastasis from the primary tumour and is used to predict the status of the remaining nodes in the basin. We succeeded in detecting SNs of clinically early gastric cancers by intraoperative injection of a blue dye around the tumour. In the study presented here, multiple-marker reverse transcription-polymerase chain reaction (RT-PCR) was used to detect micrometastases in SNs and results were compared with those obtained with conventional histology. Expressions of cytokeratin-18 (CK-18), carcinoembryonic antigen (CEA), human telomerase reverse transcriptase (hTRT) and MUC-1 in SNs were determined by RT-PCR and Southern blot assay. Of the 213 SNs obtained from 35 cases of gastric cancer, eight nodes (3.8%) from five patients contained metastases that could be identified by conventional histology. However, CK-18 mRNA was expressed in 15 (7.0%), CEA in 12 (5.6%), hTRT in 10 (4.7%), and MUC-1 in 12 (5.6%) nodes, with at least one mRNA marker expressed in 25 nodes (11.7%) obtained from six patients. In the five patients with nodal metastases identified by conventional histology, two had metastases in both SNs and non-SNs. And, in the 30 patients without nodal metastases identified by conventional histology, one patient with micrometastases in the SNs identified by RT - PCR and Southern blot assay also had metastases in non-SNs as identified by serial sectioning and immunostaining of CK-18. All additional metastases were detected in non-SNs located in the same lymphatic basin as the previously detected SNs. This suggests that lymph node dissection of early-stage gastric cancer in the lymphatic basin may be mandatory even for patients without histologically detectable metastases in SNs.