DNA ploidy and S-phase fraction, but not p53 or NM23-H1 expression, predict outcome in colorectal cancer patients. Result of a 5-year prospective study.

PURPOSE: The aim of this study was to determine TP53 and NM23-H1 immunoreactivity, DNA ploidy, and S-phase fraction (SPF) in a series of 160 patients undergoing resective surgery for primary operable colorectal cancer (CRC) and to establish whether these alterations have any clinical value in predicting CRC patients' prognosis. METHODS: TP53 and NM23-H1 expressions were evaluated on paraffin-embedded tissue by immunohistochemistry and DNA-ploidy and SPF on frozen tissue by flow-cytometric analysis. RESULTS: The median follow-up time in our study group was 71 months (range 34-115 months). P53 protein expression was associated with distal tumors (P<0.05) and DNA aneuploid tumors (P<0.05) tumors. DNA-aneuploidy was associated with distal tumors (P<0.01), histological grade (G3) (P<0.05), advanced Dukes' stage (C and D) (P<0.01), lymph node metastases (P<0.01) and high SPF (>18.3%) (P<0.01). The major significant predictors for both disease relapse and death were advanced Dukes' stage, DNA-aneuploidy, and high SPF, while lymphohematic invasion was the only independent factor for relapse and non-curative resection for death. CONCLUSIONS: Our results indicate that DNA aneuploidy and high SPF are associated in CRC with a poor clinical 5-year outcome, while in contrast the prognostic role of TP53 and NM23-H1 expression is still to be clarified.

Specific codon 13 K-ras mutations are predictive of clinical outcome in colorectal cancer patients, whereas codon 12 K-ras mutations are associated with mucinous histotype.

BACKGROUND: K-ras mutations, one of the earliest events observed in colorectal carcinogenesis, are mostly found in codons 12 and 13, and less frequently in codon 61, all three of which are estimated to be critical for the biological activity of the protein. Nevertheless the prognostic significance of such mutations remains controversial. Our purpose was to assess whether any or specific K-ras mutations in primary colorectal cancer had prognostic significance and were linked to clinico-pathological parameters. PATIENTS AND METHODS: Paired tumor and normal tissue samples from a consecutive series of 160 untreated patients (median of follow up 71 months), undergoing resective surgery for primary colorectal carcinoma, were prospectively studied for K-ras mutations by PCR/single strand conformation polymorphism sequencing. RESULTS: Seventy-four of the 160 (46%) primary colorectal carcinomas presented mutations in K-ras: 54% in codon 12, 42% in codon 13 (particularly G-->A transition) and 4% in both. Codon 12 K-ras mutations were associated with mucinous histotype (P <0.01), while codon 13 K-ras mutations were associated with advanced Dukes' stage (P <0.05), lymph-node metastasis (P <0.05) and high S-phase fraction (P <0.05). Multivariate analysis showed that codon 13 K-ras mutations, but not any mutation, were independently related to risk of relapse or death. CONCLUSIONS: Our results suggest that codon 12 K-ras mutations may have a role in the mucinous differentiation pathway, while codon 13 mutations have biological relevance in terms of colorectal cancer clinical outcome.

DNA aneuploidy and high proliferative activity but not K-ras-2 mutations as independent predictors of clinical outcome in operable gastric carcinoma: results of a 5-year Gruppo Oncologico dell'Italia Meridonale (GDIM) prospective study.

BACKGROUND: The prognostic value of DNA ploidy, S-phase fraction (SPF) and K-ras-2 mutations in gastric carcinoma (GC) has not yet been clearly defined. The aim of this study was to clarify the association between biomolecular variables, tumor characteristics, and clinical outcome in GC patients. METHODS: Resected specimens from a consecutive series of 69 patients with GC who underwent potentially curative surgery were studied prospectively. DNA ploidy and SPF were assessed by flow cytometry on multiple frozen tumor samples, whereas K-ras-2 mutations were detected by polymerase chain reaction followed by single-strand conformation polymorphism. All the patients involved in this study were followed up for a mean of 95 months. RESULTS: DNA aneuploidy was present in 72% of the cases (50 of 69), whereas 10% of these (5 out of 50) showed multiclonality. Mutations of K-ras-2 were detected in 8% of the tumors (5 of 63). Both DNA ploidy and SPF were associated with TNM stage (American Joint Committee on Cancer [AJCC] staging system) and node status. Moreover, DNA aneuploidy was significantly related to high SPF. K-ras-2 mutations were not associated with clinicopathologic variables or flow cytometric indicators. At univariate analysis, advanced TNM stage, node involvement, diffuse histotype, depth of invasion, DNA aneuploidy, and high SPF proved to be significantly related to quicker tumor relapse and to shorter overall patient survival. With multivariate analysis, DNA aneuploidy, high SPF, and depth of invasion were related to risk of tumor relapse and patient death, whereas diffuse histotype was independently related to patient risk of tumor relapse. CONCLUSIONS: DNA ploidy and SPF, when associated with clinicopathologic staging, might be useful for the identification of GC patients who have different risks for death or relapse of disease.

Prognostic significance of DNA ploidy, S-phase fraction, and tissue levels of aspartic, cysteine, and serine proteases in operable gastric carcinoma.

A consecutive series of 63 untreated patients undergoing surgical resection for stage I-IV gastric adenocarcinomas (GCs) has been prospectively studied. Our purpose was to analyze the predictive relevance of DNA ploidy, S-phase fraction (SPF), and tissue levels of lysosomal proteinases cathepsin D (CD), cathepsin B (CB), cathepsin L (CL), and urokinase-type plasminogen activator (uPA) and that of the intracellular cysteine proteinase inhibitor stefin A on clinical outcome. All of the patients taking part in this study were followed up for a median of 73 months. DNA aneuploidy was present in 71% of the cases (45/63), whereas 9% of these (4/45) showed multiclonality. Both DNA ploidy and SPF were associated with tumor-node-metastasis (TNM) stage and node status, whereas only DNA ploidy was related to depth of invasion. CB, CL, uPA, but not CD, levels were significantly higher in GC as compared to paired normal mucosa, whereas stefin A levels were lower in tumor tissues. CB levels were significantly associated with TNM stage, nodal status, histological grade, and DNA ploidy. At univariate analysis, only node involvement, advanced TNM stage, DNA aneuploidy, and high SPF proved to be significantly related to quicker relapse and to shorter overall survival, whereas depth of invasion was related only to survival. With multivariate analysis, only high SPF (>15.2%) was related to risk of relapse (RR = 8.50), whereas high SPF and DNA aneuploidy were independently related to risk of death (RR = 1.88 and 2.09, respectively). Our preliminary prospective study has identified SPF and DNA ploidy as important biological indicators for predicting the outcome of patients with GC.

Hereditary common cancers: molecular and clinical genetics.

This review focuses on the functional role and structural features of the genes involved in common hereditary cancers. Most of these tumors are sporadic and the genetic alterations responsible for their genesis take place over several cell generations; nevertheless, 5 to 10% of the human tumors are hereditary, with a rapid development. Cancer susceptibility genes have been classified as "gatekeepers" (e.g. RB1, ki-ras) and "caretakers" (e.g. hMLH1 and hMSH2, BRCA1). The first step in identifying individuals at high risk of developing a specific inherited form of cancer, and who should therefore undergo genetic tests, is the detailed construction of family history (an accurate cancer family history that includes at least three generation pedigrees, an appropriate cancer risk assessment and an effective genetic counseling). At present, the most useful methods of risk assessment are those performed on the following genes: BRCA1 and BRCA2 especially for hereditary breast and ovarian cancer, hMLH1 and hMSH2 for hereditary non polyposis colorectal cancer, APC for familial adenomatous polyposis, ret for medullary thyroid carcinoma, p53 for the Li-Fraumeni syndrome, p16 for melanoma and RB1 for retinoblastoma. In conclusion, the development of new diagnostic tests will permit a more accurate assessment of risk in individuals who have not so far shown any sign or symptom of the disease.