Microsatellite status and cell cycle associated markers in rectal cancer patients undergoing a combined regimen of 5-FU and CPT-11 chemotherapy and radiotherapy.

Abstract

BACKGROUND:

Microsatellite instability (MSI) and expression of cell cycle-related markers may predict a favorable outcome in colorectal cancer patients. The aim of this study was to elucidate the molecular profiles of patients with rectal cancers treated with neoadjuvant chemotherapy (5-Fluorouracil and CPT-11), radiotherapy and surgery that correlate with response to therapy.

PATIENTS AND METHODS:

Fifty-seven patients with rectal cancer were treated with the same preoperative chemotherapy regimen, radiotherapy (45 to 54 Gy) followed by surgery. The microsatellite status, the expression of the mismatch repair proteins MLH1 and MSH2 and p21WAF1/C1PI, p27, bcl-2, topoisomerase II (topo II) and Ki-67 were assessed in the pretreatment biopsies. The response to adjuvant therapy was categorized in the resected specimens as complete response (CR, no microscopic residual tumor present) and partial response (PR, tumor present).

RESULTS:

p21WAF1/C1PI, expression characterized the CR with 12 out of 30 tumors (40%) positive for this marker. None of the patients whose tumors did not express p21WAFI/C1PI (10 patients) was a CR (p=0.011). Overall, the tumors with CR also showed higher expression of bcl-2, Ki-67, topo II and p27. However, p53 was more frequently expressed in the PR tumors. Tumors with high microsatellite instability showed CR (3/5, 60%) more often than PR, whereas tumors with stable microsatellites showed PR (26/36, 80%) more often than CR (p=0.099).

CONCLUSION:

We conclude that a molecular profile characterized by high microsatellite instability with loss of mismatch repair protein expression and p21WAF1/C1PI is predictive of an improved response to neoadjuvant treatment with 5-FU, CPT-11 and radiation therapy.

• Authors: Mona Charara, Tina Bocker Edmonston, Susan Burkholder, Rhonda Walters, Pramila Anne, Edith Mitchell, Robert Fry, Bruce Boman, Deborah Rose, Richard Fishel, Walter Curran, Juan Palazzo
• Journal: Anticancer research (Anticancer Res) 2004 Sep-Oct Vol. 24 Issue 5B Pg. 3161-7 ISSN: 0250-7005 [Print] Greece
• PMID: 15510606 (Publication Type: Clinical Trial, Clinical Trial, Phase I, Clinical Trial, Phase II, Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• CDKN1A protein, human
• Cyclin-Dependent Kinase Inhibitor p21
• Cyclins
• Tumor Suppressor Protein p53
• Cyclin D1
• Irinotecan
• Fluorouracil
• Camptothecin

Topics

• Adult
• Aged
• Antineoplastic Combined Chemotherapy Protocols (therapeutic use)
• Camptothecin (administration & dosage, analogs & derivatives)
• Cell Cycle (drug effects, radiation effects)
• Chemotherapy, Adjuvant
• Cyclin D1 (biosynthesis)
• Cyclin-Dependent Kinase Inhibitor p21
• Cyclins (biosynthesis)
• Female
• Fluorouracil (administration & dosage)
• Humans
• Irinotecan
• Male
• Microsatellite Repeats (genetics)
• Middle Aged
• Radiotherapy, Adjuvant
• Rectal Neoplasms (genetics, metabolism, pathology, therapy)
• Tumor Suppressor Protein p53 (biosynthesis)