The complete coding region of the p53 gene was sequenced from 316 consecutively presented breast cancers, of which 97 were lymph node positive and 206 were node negative. The p53 status was related to prognosis and effect of adjuvant therapy. In all, 69 individual mutations, 29 in node-positive tumours, were demonstrated throughout the whole coding sequence. The mutation sites were partly different for node-positive and node-negative patients. p53 mutations in the evolutionary conserved regions II and V were associated with significantly worse prognosis. Adjuvant systemic therapy, especially with tamoxifen, along with radiotherapy seemed to be of less value to p53 mutation- and lymph node-positive tumours.

Complete sequencing of the p53 gene provides prognostic information in breast cancer patients, particularly in relation to adjuvant systemic therapy and radiotherapy

Background: Mutations in the p53 tumor suppressor gene (also known as TP53) have been detected in a wide variety of human cancers. In breast cancer, the presence of p53 gene alterations has been associated with worse prognosis. Purpose: We compared a complementary DNA (cDNA)-based sequencing method and an immunohistoch emical (IHC) method for their abilities to detect p53 mutations in breast cancer specimens. In addition, we determined the prognostic value of information obtained when these two methods were used. Methods: Specimens from 316 primary breast tumors were evaluated for the presence of mutant p53 protein by use of the mouse monoclonal antibody Pab 1801 (that recognizes both wild-type and mutant forms of p53) and standard IHC methods. In addition, the entire coding region of p53 genes expressed in these tumors was screened for mutations by combining reverse transcription, the polymerase chain reaction, and DNA sequencing. Probabilities for overall survival (OS), breast cancer-corrected survival (BCCS; death from breast cancer is the considered event), and relapse-free survival (RFS) were estimated by use of the Kaplan-Meier method, and survival curves for different patient subgroups were compared by use of the logrank method. All reported P values are from two-sided tests. Results: Sixty-nine (22%) of 316 tumors had p53 gene mutations detected by the cDNAbased sequencing method; only 31 (45%) of these mutations were located in evolutionary conserved portions of the p53 coding region. Sixty-four tumors (20% of the total) had elevated levels of p53 protein as detected by IHC, suggesting the presence of mutations. Of the sequencing-positive tumors (i.e., p53 mutant), 23 exhibited negative IHC reactions, indicating that IHC failed to detect 33% of the mutations. Furthermore, 19 of the IHC-positive tumors were sequencing negative (i.e., p53 wild-type), suggesting a 30% false-positive frequency with IHC. Four tumors (1.3% of the total) could not be analyzed by the cDNA-based sequencing method, and three tumors (1% of the total) could not be analyzed by IHC. The 5-year estimates for RFS, BCCS, and OS were significantly shorter for patients with p53 sequencing-positive tumors than for patients with sequencing-negative tumors (P = .001, P = .01, and P - .0003, respectively). Patients with IHC-positive tumors showed reduced survival in all three categories when compared with those with IHCnegative tumors, but the differences were not statistically significant. Conclusions: Use of a cDNA-based sequencing method to determine the status of the p53 gene in primary breast cancers yielded better prognostic information than IHC performed with the Pab 1801 monoclonal antibody. [J Natl Cancer Inst 1996;88:173-82]

The p53 gene in breast cancer: prognostic value of complementary DNA sequencing versus immunohistochemistry.

Mutations in the gene coding for the p53 tumor suppressor protein are common in a variety of human cancers. To assess the role of a putative mutated p53 protein in human lung cancer, a monoclonal antibody recognizing it was used in an immunoperoxidase detection system. A total of 114 cases of Stage I and II adenocarcinomas and squamous cell carcinomas were studied. The staining pattern was always intranuclear and heterogeneous. When the median or mean survival time was compared between cases, p53 accumulation had a statistically significant negative prognostic value. This was supported by a Kaplan-Meier survival plot of p53 producers and nonproducers. In 7 of 24 Stage II cases that were negative for p53 in the primary tumor, metastatic regional lymph nodes were p53-positive. These latter cases had greatly reduced survival times. Thus, p53 accumulation in primary tumors (and regional lymph nodes) may identify a subgroup of lung cancer patients with a prognosis of more aggressive disease.

https://cancerres.aacrjournals.org/content/canres/52/17/4828.full.pdf

Accumulation of p53 protein correlates with a poor prognosis in human lung cancer.

Two hundred and twelve archival bladder-cancer biopsy specimens were analyzed immunohistochemically to detect over-expression of p53 protein. The results of immunohistochemical analysis were correlated to established histological and quantitative prognostic factors and survival of patients during a mean follow-up period of more than 10 years. Twentynine percent of tumours were positive for p53 protein, and over-expression was associated with high histological grade, non-papillary growth architecture, dense inflammatory cell reaction, DNA aneuploidy, high S-phase fraction, high mitotic frequency and high SD of nuclear area. Progression in T, N and M categories was significantly related to over-expression of p53 protein. In univariate survival analysis, over-expression of p53 predicted poor outcome in the entire cohort, in papillary tumours and in muscle-invasive tumours but not in superficial tumours. In a multivariate survival analysis, over-expression of p53 oncoprotein had no independent prognostic value over clinical stage and mitotic index. The results confirm that p53 is involved in the growth regulation of bladder cancer and is certainly a subject for detailed analysis of specific mutations.

Over‐expression of p53 nuclear oncoprotein in transitional‐cell bladder cancer and its prognostic value

The ultimate goal of basic cancer research is to provide a theoretical foundation for rational approaches to improve cancer therapy. Our extensive insight into the biology of the p53 tumour suppressor and the clinical behaviour of tumours harbouring p53 mutations indicates that information concerning p53 will be useful in diagnosis and prognosis, and may ultimately produce new therapeutic strategies. At the same time, efforts to understand the clinical implications of p53 mutations have revealed conceptual and technical limitations in translating basic biology to the clinic. The lessons learned from p53 may lay the groundwork for future efforts to synthesize cancer gene function, cancer genetics and cancer therapy.

Clinical implications of p53 mutations

In a study of 90 breast cancer patients, tumour p53 protein expression was determined by immunohistochemistry using the monoclonal antibody PAb1801. Patient lymph node status and Bloom's grade were determined, and both oestrogen and progesterone status assessed, also by immunohistochemistry. Lymph node status, tumour grade, and progesterone receptor status all had a significant influence on survival. Patients with p53-positive tumours showed poorer survival but this did not achieve significance. p53 protein expression showed a significant relationship to high tumour grade and a weak correlation with negative oestrogen receptor status. The data suggest taht p53 protein expression may be a marker of more aggressive carcinomas but that the prognostic power of expression is likely to be weak and unlikely, therefore, to be of clinical value. The results do not resolve whether detectable p53 protein expression represents a random product of dedifferentiation, or an important feature of the malignant phenotype, playing a key role in tumour behaviour. The number of patients in our study is small, however, and investigation of a larger series is clearly indicated.

A. Sawan

Papers

p53 expression in human breast cancer related to survival and prognostic factors: an immunohistochemical study.