Quantification of micrometastases in lymph nodes of colorectal cancer using real-time fluorescence polymerase chain reaction

Prognostic impact of CK-20-positive cells in peripheral venous blood of patients with gastrointestinal carcinoma

Despite curative tumor resection, about 30%-50% of patients with locally advanced gastrointestinal (GI) carcinoma develop tumor recurrence which may be caused by pre- or intraoperative tumor cell dissemination. We examined the combination of optimized density gradient centrifugation with a CK-20 reverse transcriptase-polymerase chain reaction to detect and quantify circulating tumor cells in peripheral blood. Peripheral venous blood (20 ml) of patients with GI carcinomas was collected during primary tumor staging before and after the endoscopy procedure. CK-20 expression in peripheral venous blood was found in 22 of 82 patients (26.8%) with a nonsignificant difference between the upper GI tract (23.9%) and the lower GI tract (30.5%). The correlation with clinical outcome (24-month-survival) revealed a significantly worse prognosis (p < 0.05) of CK-20-positive patients with carcinoma of the upper GI tract and a trend toward a worse prognosis for patients with carcinoma of the lower GI tract. Quantification of CK-20 expression in peripheral blood showed a significantly higher circulating CK-20 copy number (median: 2816) in patients with metastatic tumors than in those with non-metastatic tumors (median: 983) (p < 0.05). For a subset of 42 primarily operated patients, we correlated the detection rate with UICC (International Union Against Cancer) staging categories. In contrast to the upper GI tract, the detection rate of patients with carcinoma of the lower GI tract showed a trend toward tumor size (pT) and a significant correlation with the presence of distant metastases (pM) (p < 0.01) and the postoperative residual tumor status (R) (p < 0.01). The endoscopy procedure did not lead to an increased detection of CK-20 expression.

Detection of lymph nodes micrometastases in Dukes’ A and B colorectal cancer using anti-cytokeratin antibodies AE1/AE3

AIM: To detect lymph nodes micrometastases and analyze its correlation with clinicopathological parameters in Dukes’ A and B colorectal cancer patients.

METHODS: One hundred and fourteen patients with colorectal cancer (Dukes’ A 16; Dukes’ B 98) undergoing curative operation without histological lymph nodes metastases were studied between 2001 and 2003. A total of 2 481 lymph nodes were analyzed using monoclonal cytokeratin antibody AE1/AE3 (DAKO, Carpinteria, CA) for immunohist-ochemistry.

RESULTS: In total, 33 (29%) patients were positive for cancer cell by immunohistochemistry. In 31 (94%) patients of them positive nodes showed single tumor cell or small groups of tumor cells; and tumor deposits measuring 0.2 and 0.37 mm in diameter in another 2 (6%) patients. Micrometastases were mainly located in the subcapsular sinus or paracortical sinus. There was no correlation between the positive lymph nodes and gender, age, tumor site, tumor size, histological type, histological grade, invasion depth, Dukes’ staging and microsatellite instability (P>0.05).

CONCLUSION: Our findings suggest that immunohist-ochemical technique using monoclonal cytokeratin antibody AE1/AE3 may be a sensitive and reliable method for detecting lymph nodes micrometastases in Dukes’ A and B colorectal cancer. The clinical significance of lymph nodes microme-tastases is still not confirmed.

Quantification of colorectal cancer micrometastases in lymph nodes by nested and real-time reverse transcriptase-PCR analysis for carcinoembryonic antigen

PURPOSE

Reverse-transcriptase PCR (RT-PCR) assays for carcinoembryonic antigen (CEA) have been described to identify lymph node micrometastases. These assays are not quantitative and can be confounded by false-positive results. The purpose of this study was to determine whether quantification of CEA in lymph nodes could more readily identify clinically relevant groups.

EXPERIMENTAL DESIGN

Specimens included 400 lymph nodes from 64 patients undergoing colon resections. Specimens were tested by immunohistochemistry and by RT-PCR using nested primers for CEA. Specimens from 59 patients that were positive by nested RT-PCR were further quantified by detection of CEA mRNA fluorescence increase at a threshold PCR cycle.

RESULTS

CEA was detected by nested RT-PCR analysis in 4 of 34 (12%) nodes of nonneoplastic disease, 2 of 13 (15%) nodes from T(1)N(0) patients, 32 of 81 (40%) nodes of T(2)N(0) patients, 49 of 109 (45%) nodes from T(3)N0 patients, and 92 of 163 (56%) nodes from T(1-4)N(1-2) patients. The overall presence of any RT-PCR-detectable CEA in nodes did not differentiate patient groups. Immunohistochemistry was positive in nodes from 7% of T(3)N(0) patients and 100% of T(1-3)N(1-2) patients. CEA quantification revealed that 0 of 7 patients with nonneoplastic disease and 2 of 17 (12%) patients with stage I T(1-2)N(0) cancers had one or more lymph nodes with >/=1.0 x 10(2) CEA transcripts per sample. In contrast, 4 of 13 (31%) patients with stage II T(3)N(0) cancer and 10 of 22 (45%) stage III patients with known metastases had lymph nodes with >/=1.0 x 10(2) CEA transcripts.

CONCLUSIONS

These data suggest that quantification of CEA levels in lymph nodes may more accurately identify patients at risk for cancer recurrence than does routine nested RT-PCR or immunohistochemistry.

Combination of IFN- and 5-Fluorouracil Induces Apoptosis through IFN-α/β Receptor in Human Hepatocellular Carcinoma Cells

Purpose: Several studies showed the effectiveness of combination therapy with IFN-α and 5-fluorouracil (5-FU) for advanced hepatocellular carcinoma. However, only little is known about the underlying mechanism of combination therapy. In the present study, we examined whether apoptosis through IFN-α/β receptor (IFN-α/βR) was associated with the effects of combination therapy.

Experimental Design: HuH7, PLC/PRF/5, HLE, and HLF were treated with IFN- (500 units/mL), 5-FU (0.5 μg/mL), or their combination for 10 days. In addition, IFN-α/βR gene transfer with combination therapy was done.

Results: Ten-day treatment by combination therapy resulted in &gt;80% cell growth inhibition. Terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling analysis showed synergistic effects for combination therapy on PLC/PRF/5, HLE, and HLF. Concordant results were obtained with DNA fragmentation. Moreover, there was an evidence showing that changes in the expression of Bcl-2 family lead to apoptosis. On the other hand, the expression of IFN-α/βR and up-regulation of α-phospho–signal transducer and activator of transcription 1, IFN regulatory factor-1 by combination therapy were observed in all cell lines. Furthermore, IFN-α/type 2 IFN receptor long form–transfected HuH7 cells treated with combination therapy showed strong DNA fragmentation compared with nontransfected or transfected with IFN-α- and 5-FU-treated HuH7.

Conclusions: Our results showed that combination of IFN-α plus 5-FU strongly induced cell growth inhibition of human hepatocellular carcinoma cells and indicated that oneof the direct mechanisms of combination therapy may in part be attributable to alterations in induction of apoptosis through IFN-α/βR.

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

PURPOSE

Inconsistent conclusions have been drawn about the clinical significance of micrometastases in lymph nodes (LNs) of node-negative colorectal cancer (CRC) patients. We performed a comparative study of detection of micrometastases using immunohistochemistry (IHC) by anti-cytokeratin antibody and carcinoembryonic antigen (CEA)-specific reverse-transcriptase polymerase chain reaction (RT-PCR) in the same patients, in an attempt to move closer to their clinical application.

PATIENTS AND METHODS

Sixty-four CRC patients, with RNA of good quality available from paraffin-embedded LN specimens, were selected from 84 stage II patients who underwent curative surgery between 1988 and 1996. We investigated associations between the presence of micrometastases by each method and prognosis.

RESULTS

Micrometastases were detected in 19 (29.6%) of 64 patients by RT-PCR and in 35 (54.7%) of 64 patients by IHC. By RT-PCR analysis, patients exhibiting a positive band for CEA mRNA had a significantly worse prognosis than those who were RT-PCR-negative, with respect to both disease-free and overall survival (P =.027 and.015, respectively). By IHC analysis, the presence of micrometastasis did not predict patient outcome in terms of either disease-free or overall survival. Infiltrating pattern of tumor growth characteristic was significantly associated with shorter disease-free survival among various clinical or pathologic factors. By multivariate Cox regression analysis, micrometastasis detected by RT-PCR and the Crohn's-like lymphoid reaction were both independent prognostic factors.

CONCLUSION

Micrometastases detected by RT-PCR, but not IHC, may be of clinical value in identifying patients who may be at high risk for recurrence of CRC and who are therefore likely to benefit from systemic adjuvant therapy.