Bisulfite sequencing analysis of the AOX1, CACNA1G and IRF8 promoters in matched adjacent normal colon (N) and KRAS-positive CRC human tumor samples (T) samples.
In these tumors, MSP results identified only methylated alleles in tumors, whereas matched adjacent normal colon mucosa contained both methylated and unmethylated PCR products.
Bisulfite sequencing analysis of the p14 ARF promoter in matched adjacent normal colon (N) and KRAS-positive CRC human tumor samples (T) samples.
In addition to the primary CRC tissue, FFPE specimens of matched adjacent normal colon tissue, lymph node metastases and distant metastases were available for 12, 18 and 7 of these patients, respectively.
Formalin-fixed paraffin embedded tissue sections of matched adjacent normal colon and tumor samples isolated from individuals with invasive or metastatic KRAS-positive CRC were de-paraffinized in Histolemon-Erba RS solution (Carlo Erba Reagents, France) four times for 10 min at room temperature.
Four pairs of CRC biopsies and the matched adjacent non-cancerous colon tissues were obtained from each patient during surgery, and immediately frozen and maintained in liquid nitrogen until further use.
Overall, MSP analysis within the 5′ CpG island of p14/ARF flanking exon 1β identified coexistence of methylated and unmethylated alleles in tumors and matched adjacent normal-appearing colon mucosa in 91 of the 98 patients.
As shown in Table 1, sphere-forming characteristics were frequently observed in colon tumour cells (10 of 13) and less in matched adjacent normal tissue cell populations (2 of 13).
Using 15 pairs of tumor and matched adjacent normal tissues from five cancer types (breast, lung, prostate, colon-recta and cervical cancer), three pairs for each cancer type, the relative expressions of 32 randomly chosen common cancer genes from the identified signature gene set were initially screened by QRT-PCR analysis, as described in a previous study [39].
Thirteen independent surgically resected colon tumour specimens of varying pathology stages, together with matched adjacent normal tissue, were dissected to obtain single cell suspensions.
