Survey of molecular profiling during human colon cancer development and progression by immunohistochemical staining on tissue microarray

Abstract

Aim: To explore the molecular events taking place during human colon cancer development and progression through high-throughput tissue microarray analysis.

Methods: We constructed two separate tissue microarrays containing 1.0 mm or 1.5 mm cylindrical samples acquired from 112 formalin-fixed and paraffin-embedded blocks, including carcinomas (n = 85), adenomatous polyps (n = 18), as well as normal para-cancerous colon tissues (n = 9). Immunohistochemical staining was applied to the analysis of the consecutive tissue microarray sections with antibodies for 11 different proteins, including p53, p21, bcl-2, bax, cyclin D1, PTEN, p-Akt1, beta-catenin, c-myc, nm23-h1 and Cox-2.

Results: The protein expressions of p53, bcl-2, bax, cyclin D1, beta-catenin, c-myc, Cox-2 and nm23-h1 varied significantly among tissues from cancer, adenomatous polyps and normal colon mucosa (P = 0.003, P = 0.001, P = 0.000, P = 0.000, P = 0.034, P = 0.003, P = 0.002, and P = 0.007, respectively). Chi-square analysis showed that the statistically significant variables were p53, p21, bax, beta-catenin, c-myc, PTEN, p-Akt1, Cox-2 and nm23-h1 for histological grade (P = 0.005, P = 0.013, P = 0.044, P = 0.000, P = 0.000, P = 0.029, P = 0.000, P = 0.008, and P = 0.000, respectively), beta-catenin, c-myc and p-Akt1 for lymph node metastasis (P = 0.011, P = 0.005, and P = 0.032, respectively), beta-catenin, c-myc, Cox-2 and nm23-h1 for distance metastasis (P = 0.020, P = 0.000, P = 0.026, and P = 0.008, respectively), and cyclin D1, beta-catenin, c-myc, Cox-2 and nm23-h1 for clinical stages (P = 0.038, P = 0.008, P = 0.000, P = 0.016, and P = 0.014, respectively).

Conclusion: Tissue microarray immunohistochemical staining enables high-throughput analysis of genetic alterations contributing to human colon cancer development and progression. Our results implicate the potential roles of p53, cyclin D1, bcl-2, bax, Cox-2, beta-catenin and c-myc in development of human colon cancer and that of bcl-2, nm23-h1, PTEN and p-Akt1 in progression of human colon cancer.

Figure 1

HE staining of 4-μm thick section of the tissue microarray.

Figure 2

Immunophenotype of the investigated antigens (p53, p21, cyclin D1, bcl-2 and bax) in colon cancer (original magnification x 200). Positive stainings of p53, p21 and cyclin D1 were located in the cell nuclei, while those of bcl-2 and bax were in the cytoplasm.

Figure 3

Immunophenotype of the investigated antigens (Cox-2 and nm23-h1) in colon cancer (original magnification x 200). The protein expressions of Cox-2 and nm23-h1 were detected in the cytoplasm.

Figure 4

Immunophenotype of the investigated antigens (PTEN, p-Akt1, β-catenin and c-myc) in colon cancer (original magnification x 200). Expressions of PTEN, p-Akt1, β-catenin and c-myc were detected in the cell cytoplasm.