The TP53 codon 72 polymorphism may affect the function of TP53 mutations in breast carcinomas but not in colorectal carcinomas.

An Arg/Pro polymorphism in codon 72 of the TP53 gene was analyzed in blood samples from 390 breast and 162 colorectal cancer patients previously investigated for TP53 mutations in their tumors. Among the breast cancer cases, 228 were homozygous for the Arg72 allele, of which, 65 (28.5%) also had a TP53 mutation in their tumors. In contrast, of 26 cases that were homozygous for the Pro72 allele, only 1 case (3.8%) had a TP53 mutation in the tumor (P = 0.004). Cloning the TP53 gene from tumor DNA followed by sequencing was performed in 14 heterozygotes with tumor mutation, and 9 of the mutations resided on the Arg72 allele. Among the colorectal cancer cases, no difference in mutation frequency was seen between the two different homozygotes, 40 TP53 mutations in 97 Arg72 homozygous cases (41.2%) versus 7 in 16 Pro72 homozygous cases (43.8%). These results suggest a selective growth advantage for cells carrying a type of TP53 mutation seen in breast carcinomas when the mutation resides on an Arg72 allele.     

Sarcomas in TP53 germline mutation carriers: a review of the IARC TP53 database

BACKGROUND:

Sarcoma is the index diagnosis of Li‐Fraumeni syndrome (LFS), a familial predisposition to cancer that also includes brain cancer, breast cancer, and adrenal cortical carcinoma. Germline mutations in the TP53 gene are detected in approximately 80% of families that fulfill LFS criteria and in 15% to 25% of families that fulfill criteria for Li‐Fraumeni‐like syndrome (LFS), a group of related syndromes with broader clinical criteria.

METHODS:

The authors of this report used the International Agency for Research on Cancer TP53 database to analyze the types, age at onset and mutation patterns of sarcoma in TP53 mutation carriers. Those data were compared with sarcoma types in the general population of Caucasians using data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program.

RESULTS:

Overall, sarcomas represented 25% of tumors in TP53 mutation carriers, and 95.6% occurred before age 50 years compared with 38.3% before age 50 years in the SEER data set. Sarcomas were more likely to be rhabdomyosarcoma in carriers aged <5 years (odds ratio [OR], 11.6; 95% confidence interval [CI], 6.1‐21.9) and osteosarcoma in carriers at any age (aged <20 years: OR, 1.41; 95% CI, 1.02‐1.94; age >20 years: OR, 4.61; 95% CI, 2.72‐7.83). Early sarcoma (at age <20 years) was associated with missense mutations in exons encoding the DNA‐binding domain of p53 protein. Conversely, p53 null mutations (frameshift, splice sites, nonsense) and mutations outside the DNA‐binding domain were associated with leiomyosarcoma (OR, 10.1; 95% CI, 3.4‐29.9), a type of sarcoma that occurred after age 20 years.

CONCLUSIONS:

The current results further demonstrated genotype‐phenotype correlations and age‐dependent variations in sarcoma types in carriers of germline TP53 mutations. Cancer 2012;. © 2011 American Cancer Society.     

Abnormal expression of the ATM and TP53 genes in sporadic breast carcinomas.

The ataxia telangiectasia gene (ATM) has been implicated as a risk factor in the development of sporadic breast carcinomas. ATM protein expression was analyzed by immunohistochemistry in 17 breast carcinomas with two monoclonal antibodies whose immunohistochemical use was first validated by comparing the immunoreactivity observed in spleen samples from ataxia telangiectasia and trauma patients. In normal breast ducts, ATM showed nuclear expression in the epithelial but not in the myoepithelial cells. In contrast, this nuclear expression was absent or low in the epithelial cancer cells in 10 of 17 (59%) of the tumors studied. Allelic imbalance in the ATM gene was found in three of seven tumors examined. Two of these showed reduced ATM protein expression, but this did not correlate with the presence of ATM mutations in the tumor DNA detected by restriction endonuclease fingerprinting screening. These results suggest that the reduced ATM protein expression could be attributable, in certain tumors, to deletions or rearrangements within or close to the ATM gene. Positive p53 immunostaining was found in 10 tumors, with TP53 mutations detected in 8. Three tumors had both low ATM expression and mutated TP53. Our results indicate that in the majority (15 of 17) of the sporadic breast carcinomas examined, not only is the functionality of the ATM-p53-mediated DNA damage response compromised, but also other signaling pathways activated by these two multifunctional proteins are likely to be impaired, which could be a contributing factor to tumor development and progression.     

TP53 mutations in primary breast carcinomas from white and African-Brazilian patients

We have attempted to determine the incidence, nature and clinical significance of TP53 mutation in a group of white (242 cases) and African-Brazilian (52 cases) patients with breast cancer. The interethnic admixture as estimated by STR markers showed that white subjects displayed 67.9+/-0.4%, 25.0+/-1.7% and 7.0%+/-1.6% and the black populations had 34.4+/-1.9%, 56.2+/-1.9 and 9.4+/-2.2% respectively of European, African and Amerindian genes. Clinical parameters such as age, lymph node status and steroid receptors were similar in both groups. African-Brazilian patients presented more advanced lesions. Mutation screening was performed using polymerase chain reaction-single strand conformation analysis followed by sequencing. Compared to whites (13.6%), a relatively high frequency of TP53 mutation was found in blacks (32.7%) (p=0.001). African-Brazilian women have a larger proportion of mutations in exons 5 and 7, whereas white women have more mutations in exon 8. Mutations within exon 4 were found only in tumors of white patients. The spectra of TP53 mutations show that A:T-->G:C nucleotide transversion and G:C-->C:G transition were more common in African-Brazilian women whereas G:C-->T:A transversion occurs very frequently in whites. A high prevalence of G:C-->A:T nucleotide transitions and deletions was detected in both groups. No association was found between p53 gene mutation and tumor or clinical parameters independently of the ethnic group. With a median follow-up of 35.6 months for whites and 43.4 months for the blacks, no differences in overall survival were found. If white patients were stratified according to the type and location of TP53 mutations, patients with mutations affecting amino acids directly involved in DNA or Zn binding displayed a poor prognosis. The pattern of mutations found in our population seems to reflect a base line pattern observed in populations with similar ethnic profile with some modifications, which might be derived from specific etiological factors.     

TP53 mutation patterns in breast cancers: searching for clues of environmental carcinogenesis

Mutations in the tumour suppressor gene TP53 occur in about 30% of breast cancers. We have used the IARC TP53 mutation database to analyse the pattern of mutations in breast cancers (1392 mutations). The global pattern of mutations is similar to the one of most other cancers, but there is an excess of transversions on G bases in tumours from Western (USA and Europe) as compared to Eastern (Japan) countries. Moreover, the patterns of inherited TP53 mutations associated with breast cancer, differ from those of somatic mutations. These differences support the hypothesis that a fraction of breast cancer mutations occur as a consequence of environmental exposures.     

Microcysts and breast cancer: a study of biological markers in archival biopsy material

Thermography is a technique to measure the body surface temperature and is used in medical applications. We evaluated its prognostic value in 340 female patients with unilateral invasive breast cancer without distant metastases. The difference of mean temperatures of the tumor area and corresponding area of the contralateral breast was defined as AT. The patients with hot tumors (delta T > or = 0.9 degrees C) had significantly worse disease free and specific survival than those with cold tumors (delta T < 0.9 degrees C) (p = 0.0003 and p < 0.0001, respectively). AT was significantly correlated with tumor size, histological nodal status and nuclear grade, positively. But AT did not have any relation with estrogen receptor status. Multivariate analyses including those conventional prognostic factors showed that AT was a marginally significant prognostic factor for disease-free survival (hazard ratio (HR) = 1.62; 95% confidence interval (CI) = 0.99-2.66, p = 0.0557) and an independent significant prognostic one for disease specific survival (HR = 1.95; 95% CI = 1.09-3.49, p = 0.0251). However, AT did not have prognostic impact on the node negative patients. AT might be a useful prognostic factor in node positive breast cancer, especially in patients who plan to be treated with preoperative systemic therapy.     

TP53 mutation and p53 overexpression for prediction of response to neoadjuvant treatment in breast cancer patients.

The value of p53 to predict the cytotoxic effect of two commonly used chemotherapy regimens was assessed in patients with advanced breast cancer. Response to a DNA-damaging combination therapy [fluorouracil, epirubicin, cyclophosphamide (FEC] considered to induce p53-dependent apoptosis was compared with a microtubule stabilizing therapy (paclitaxel) expected to be independent of p53 function. The p53 status of the patients' breast tumors was assessed using both immunohistochemistry (IHC) and direct sequencing of the entire p53 gene. p53 findings were correlated with treatment response, and linkage between p53 function and cellular response was assessed by terminal deoxynucleotidyl transferase-mediated nick end labeling assay. In a series of 67 breast tumors, 19% had TP53 gene mutations, 40% had a positive p53 IHC, and 12% had both. In the FEC group, treatment failure was related to both the presence of TP53 gene mutations (P = 0.0029) and a positive IHC (P < 0.0001). Apoptosis was almost exclusively found in tumors having normal p53 in both parameters (P < 0.0001). In the paclitaxel group, treatment response was neither related to apoptosis nor to normal p53. Combination of sequencing and IHC results revealed a significant association between abnormal p53 and response to paclitaxel (P = 0.011). We found TP53 mutations, as well as p53 protein overexpression, to be associated with response to chemotherapy. Whereas clinical response to FEC was found to be dependent on normal p53, the cytotoxicity of paclitaxel was related to defective p53. The efficiency of paclitaxel during mitosis might be supported by lack of G1 arrest due to p53 deficiency. Therefore, patients with p53-deficient tumors may benefit from paclitaxel.     

Prognostic value of TP53 gene mutation in adjuvant treated breast cancer patients

We investigated the prognostic significance of mutation to the TP53 tumor suppressor gene in a series of 908 breast cancer patients treated with or without adjuvant therapies. The frequency of TP53 mutation detected by single strand conformation polymorphism (SSCP) was 19.4% (176/908) in the overall tumor series. In multivariate analysis, TP53 mutation was independently associated with worse survival in the overall (HR=2.1, 95% CI [1.5–3.1], P<0.0001), non-adjuvant treated (HR=2.2, 95% CI [1.2–4.2], P=0.017) and adjuvant treated (HR=2.0, 95% CI [1.3–3.1], P=0.0009) patients.     

TP53 mutations determined by targeted NGS in breast cancer: a case-control study

Background: Tumor protein 53 (TP53) gene mutations are identified in up to 37% of breast tumors especially in HER-2 positive and basal-like subtype. Previous studies have indicated TP53 mutations as a prognostic biomarker in breast cancer. However, most of these studies performed immunohistochemistry (IHC) for the detection of TP53 mutations.Aim: The purpose of our study is to evaluate the role of TP53 somatic mutations detected via next-generation sequencing (NGS) as a potential prognostic marker in patients with breast cancer.Materials and Methods: 82 female patients with Stage I–III breast cancer underwent NGS in paraffin blocks and blood samples during the period 25/09/2019 through 25/05/2021. 23 cases of somatic TP53 mutations and 23 cases of healthy controls were matched on age at diagnosis, menopausal status, histological subtype, histological grade, ki67 expression and disease stage.Results: Mean age at diagnosis was 52.35 (SD; 11.47) years. The somatic TP53 mutation NM_000546.5:c.824G>A p.(Cys275Tyr) was most frequently detected. Co-existence of PIK3CA mutation was a common finding in somatic TP53-mutant tumors (4/23; 17.4%). Disease-free survival was shorter in TP53-mutated cases (16.3 months vs. 62.9 months). TP53 pathogenic somatic mutations were associated with a 8-fold risk of recurrence in the univariate Cox regression analysis (OR = 8.530, 95% CI: 1.81–40.117; p = 0.007).Conclusions: Our case-control study suggests that TP53 somatic mutations detected by next-generation sequencing (NGS) are associated with an adverse prognosis in breast cancer.     

The R337H mutation in TP53 and breast cancer in Brazil

Mutations in FLCN cause Birt-Hogg-Dubé syndrome, an autosomal dominant disorder notable for development of cutaneous fibrofolliculomas or trichodiscomas, a variety of renal tumors, and spontaneous pneumothorax due to cystic lung changes. We present a woman referred for genetic evaluation due to bilateral parotid gland tumors, who was subsequently diagnosed with Birt-Hogg-Dubé syndrome.     

Demonstration of gene-amplification by PCR in archival paraffin-embedded breast cancer tissue

Summary The polymerase chain reaction (PCR) is a powerful tool to examine genetic alterations in tumor samples. We describe a simple, rapid, nonisotopic PCR method to semi-quantitatively determine the number of gene copies in human formalin-fixed paraffin-embedded tissue. The procedure is exemplified by analysis of 15 years old breast cancer samples to determine the presence of amplification of c-erb-B2. The samples were obtained from routine specimens kept in pathological archives. Patients with amplified samples showed a poor prognosis, both for recurrences and death in breast cancer.     

Increased incidence of ERBB2 overexpression and TP53 mutation in inflammatory breast cancer

Inflammatory breast cancer (IBC) is one of the most aggressive forms of breast cancer. We studied the biological characteristics of these tumours by comparing the overexpression of oncogenes ERBB2, MYC, CCND1 and RHOC and TP53 gene mutation rates in IBC with those found in locally advanced and not otherwise specified breast cancers. The prevalence of the TP53 mutation was much higher in IBC than in the two other types of cancer (57% vs 30). Unexpectedly, however, in IBC tumours, histological grade was independent of TP53 status. In addition, ERBB2 overexpression was twice as frequent in inflammatory as in non-inflammatory tumours, whereas the frequencies of MYC, CCND1 and RHOC overexpression did not vary significantly among the three types of breast cancer. These findings suggest that IBC tumours constitute a distinct subset with a specific pathogenesis. Given the importance of TP53 and ERBB2 in the response to treatments, our observations have important therapeutic implications for the clinical management of IBC patients.     

Genomic analysis of inherited breast cancer among Palestinian women: Genetic heterogeneity and a founder mutation in TP53

Breast cancer among Palestinian women has lower incidence than in Europe or North America, yet is very frequently familial. We studied genetic causes of this familial clustering in a consecutive hospital‐based series of 875 Palestinian patients with invasive breast cancer, including 453 women with diagnosis by age 40, or with breast or ovarian cancer in a mother, sister, grandmother or aunt (“discovery series”); and 422 women diagnosed after age 40 and with negative family history (“older‐onset sporadic patient series”). Genomic DNA from women in the discovery series was sequenced for all known breast cancer genes, revealing a pathogenic mutation in 13% (61/453) of patients. These mutations were screened in all patients and in 300 Palestinian female controls, revealing 1.0% (4/422) carriers among older, nonfamilial patients and two carriers among controls. The mutational spectrum was highly heterogeneous, including pathogenic mutations in 11 different genes: BRCA1, BRCA2, TP53, ATM, CHEK2, BARD1, BRIP1, PALB2, MRE11A, PTEN and XRCC2. BRCA1 carriers were significantly more likely than other patients to have triple negative tumors (p = 0.03). The single most frequent mutation was TP53 p.R181C, which was significantly enriched in the discovery series compared to controls (p = 0.01) and was responsible for 15% of breast cancers among young onset or familial patients. TP53 p.R181C predisposed specifically to breast cancer with incomplete penetrance, and not to other Li‐Fraumeni cancers. Palestinian women with young onset or familial breast cancer and their families would benefit from genetic analysis and counseling.     

Prognostic significance of TP53 alterations in breast carcinoma.

Constant denaturant gel electrophoresis (CDGE) was used to screen 179 breast carcinomas for mutations in the conserved regions of the TP53 gene (exons 5 through 8). Mutations were found in 35 of 163 primary tumours (21%) and in 5 of 16 metastases (31%) and resided predominantly in exon 7. The majority of the mutations were G:C-->A:T transitions. Immunohistochemistry demonstrated nuclear accumulation of p53 protein in 35 of 162 primary tumours (22%) and in four of 15 metastases (27%). TP53 mutation was strongly associated with nuclear accumulation of p53 protein. In total 42 of 163 primary tumours (26%) and 5 of 16 metastases (31%) were demonstrated to contain TP53 alterations (mutation and/or nuclear protein accumulation). TP53 alteration in primary tumour was significantly associated with the following parameters: positive node status, T status > 1, negative oestrogen receptor status, negative progesterone receptor status, presence of ERBB2 gene amplification, and invasive ductal histology. Furthermore, there were statistically significant associations, independent of other prognostic factors, between TP53 alterations in primary tumour and disease-free and overall survival.     

TP53 gene mutations and protein accumulation in primary vaginal carcinomas.

Primary carcinomas from 46 patients were screened for TP53 alterations. Immunohistochemistry demonstrated nuclear TP53 protein accumulation in 22 (48%) cases using the polyclonal CM1 antiserum, whereas 15 (33%) cases showed positive nuclear staining with the mononuclear antibody PAb 1801. Constant denaturant gel electrophoresis (CDGE) was used to screen 27 of the vaginal carcinomas for mutations in the conserved regions of the TP53 gene (exons 5-8). Six of these tumours (22%) contained mutations: four were found in exon 5 and two in exon 8. A total of 50% of the primary vaginal carcinomas carried a TP53 alteration. These results indicate that TP53 abnormalities may be involved in the development of these tumours. However, there was no significant association between TP53 abnormalities and survival.     

Type of TP53 mutation and ERBB2 amplification affects survival in node-negative breast cancer

Alterations of TP53 and ERBB2 have been shown to play important roles in the prognosis of breast cancer. The primary objective of this study is to characterize TP53 mutation types in node negative breast cancer and investigate their prognostic value, alone and in combination with ERBB2 amplification status. TP53 mutational status (exons 2–10) and ERBB2 amplification status were determined in tumor specimens from a prospective cohort of 543 women with node-negative breast cancer. During a median follow-up of 120 months, there were 111 disease recurrences, and 81 disease-related deaths (3 with cancer; 78 from cancer). Of 543 women, 133 (24.5%) carried mutations in exons 4–9 of the TP53 gene. Seventy-one (53.4%) of these mutations were missense; whereas 62 (46.6%) were protein-truncating mutations. Women whose tumors had missense TP53 mutations were found to be at significantly higher risk of recurrence and death compared to those with wild type TP53, and they also tended to have worse prognosis compared to those with truncating mutations. Those with short truncated proteins tended to have good prognosis compared to those with long truncated proteins, but the risk of recurrence and death did not differ between those whose tumors exhibited conserved versus non-conserved mutations. Missense mutations, in combination with ERBB2 amplification, were observed in 4.6% of the tumors and dramatically affected the disease-specific survival (DSS) and disease-free survival (DFS) of the breast cancer patients. Our study suggests that the type of TP53 mutation, especially missense mutation, is a strong prognostic indicator for DFS and DSS in node-negative breast cancer, particularly in combination with ERBB2 amplification. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.