Elisabeth Janschek

TP53 genotype but not p53 immunohistochemical result predicts response to preoperative short-term radiotherapy in rectal cancer.

ObjectiveTo evaluate and compare the predictive power of p53 gene analysis versus p53 immunohistochemical staining in terms of response to preoperative short-term radiotherapy using 25 Gy in operable rectal cancer. Summary Background DataRecent studies show that p53 may be a determinant of radiosensitivity being required for induction of apoptosis in case of radiation-induced DNA damage. MethodsPreirradiation biopsy samples of 64 patients with rectal carcinoma were analyzed. Genetic alterations of the p53 gene were detected by complete direct sequencing of exons 2 to 10. Expression of the nuclear phosphoprotein p53 was assessed by immunohistochemical staining. Results were correlated with histopathology of resected specimens and follow-up data, respectively. ResultsMutations of the p53 gene were present in 45% of tumors. Patients with a normal p53 gene had a significant survival advantage. Comparing pre- and postradiotherapy T category, a reduction was seen in patients with normal p53 genotype only. A mutant p53 genotype was highly specific in indicating stable disease concerning T category after irradiation. Protein overexpression was detected in 61%. Overexpression of the p53 protein was not related to survival or response. The concordance between immunohistochemistry and sequencing was only 0.51. ConclusionsThe authors show that downstaging after short-term radiation may occur but is seen in tumors with normal p53 gene only. Moreover, p53 genotype but not p53 immunohistochemistry is predictive for response to preoperative short-term radiotherapy and patient survival.

The TP53 genotype but not immunohistochemical result is predictive of response to cisplatin-based neoadjuvant therapy in stage III non-small cell lung cancer.

BACKGROUND The cytotoxic effects of cisplatin and anthracyclins have been attributed to apoptosis induction, which has been recognized as a major function of the TP53 gene. The TP53 gene appears to be mutated in about 50% of cases of non-small cell lung cancer. A possible dependence of chemotherapy response on TP53 genotype was evaluated retrospectively in a group of patients with advanced non-small cell lung cancer and induction treatment. METHODS Patients with complete or partial remission were compared with those with stable or progressive disease with respect to TP53 genotype and overall survival. Mutations in the TP53 gene were detected by complete direct sequencing (exons 2-11). RESULTS A normal TP53 genotype proved to be significantly associated with major response to chemotherapy (P <.001). Overall, no association was found between p53 protein expression and TP53 genotype. A normal TP53 genotype was found to be highly sensitive in predicting response to treatment, whereas a mutant genotype was revealed to be specific in predicting lack of response. The difference in overall length of survival was significant between patients exhibiting a normal TP53 genotype (corresponding to those whose disease responded to chemotherapy) and patients showing mutant TP53 genotype (corresponding to those who had disease resistant to chemotherapy, P =.027). CONCLUSIONS In a small cohort of patients with advanced non-small cell lung cancer we found a direct link between normal TP53 genotype and response to cisplatin-based induction treatment and also between mutant genotype and resistance to treatment, whereas p53 immunohistochemical result was predictive of neither.

Contralateral breast cancer: molecular differentiation between metastasis and second primary cancer

Previous cancer in one breast is a strong known risk factor for cancer in the contralateral breast. Differences in tumor histology and nuclear grading are applied to distinguish between a metastatic spread and a second primary cancer, although cancers of the breast often share the same histological features. Comparison of genetic alterations in paired tumors may provide the most reliable approach for discerning clonal relationships, hence uncovering the presence or absence of multiple primary cancers. We compared tumors from 33 patients with cancer in both breasts for mutations in the p53 gene. With this molecular approach, we were able to define the relationship within paired tumors in 13 patients. The paired tumors of two patients shared the same mutation, revealing the second lesion in one case as a contralateral metachronous lymph node metastasis appearing 29 months after first surgery, and in the other as a spread to the opposite breast. In 11 patients, mutations were either discordant or solely present in one of the lesions, confirming the diagnosis of bilateral breast cancer. Histopathological evaluation had failed to provide firm diagnosis in nine out of 11 instances on account of concordances in pathological parameters such as histological type and grading.In our study, we could show that bilateral breast malignancies most frequently represent two primary breast cancers. We could also demonstrate that contralateral breast cancer spread does occur. Standard pathological assessment allowed a firm diagnosis only in the presence of different histological types.

Spectrum of germ-line MLH1 and MSH2 mutations in Austrian patients with hereditary nonpolyposis colorectal cancer

SummaryBACKGROUND: Germ-line mutations in mismatch repair genes are associated with the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome, which is characterized by susceptibility to cancer of the colon, endometrium, small bowel or urothelium at an unusually young age and with a high degree of penetration in all generations. MATERIAL AND METHODS: One hundred and nine individuals from 46 Austrian families who fulfilled the Amsterdam criteria (n = 29) or at least one of the Bethesda guidelines (n= 17) were analyzed for mutations in MLH1 and MSH2. Microsatellite instability was determined in the tumors of index persons and affected relatives. RESULTS AND CONCLUSION: High-grade instability was present in 60.6% of the tumor samples from index patients. Twenty-three germ-line DNA sequence variants in 24/46 families and four somatic mutations in three tumors were detected in MLH1 and MSH2. Fifteen mutations are novel. None of the newly identified germ-line variants was found in 100 alleles of healthy control individuals. We were able to characterize two intronic variants (MLH1 c.589-10T > A; MSH2 c.367-1G > A) with regard to their effect on mRNA. Both created new splice sites that replaced the regular ones. Germ-line mutations occurred in 44.8% of the families fulfilling the Amsterdam criteria and in 35.3% of the Bethesda patients. The detection of a pathogenic mutation was strongly correlated with microsatellite instability in the tumor DNA (p = 0.007). This study is the first comprehensive report of mutations in mismatch repair genes in Austrian patients with HNPCC.ZusammenfassungGRUNDLAGEN: Keimbahnmutationen in Mismatch-Reparatur-Genen stehen in ursächlichem Zusammenhang mit dem erblichen nicht-polypösen Kolonkarzinom-Syndrom. Diese Erkrankung zeichnet sich durch ein vermehrtes Auftreten von Karzinomen des Kolons, des Endometriums, des Dünndarmes oder des Urothels in einem außergewöhnlich jungen Alter aus. MATERIAL UND METHODEN: In dieser Studie untersuchten wir 109 Individuen aus 46 österreichischen Familien auf Mutationen in MLH1 und MSH2. Die Selektion der Patienten basierte auf den Amsterdam-Kriterien (n = 29) oder den Bethesda-Richtlinien (n = 17). In Tumorproben von Index-Patienten und erkrankten Verwandten wurde der Grad der Mikrosatelliteninstabilität ermittelt. ERGEBNISSE UND SCHLUSSBETRACHTUNG: Eine hochgradige Mikrosatelliteninstabilität konnte in 60,6% der Tumore von Index-Patienten nachgewiesen werden. In MLH1 und MSH2 wurden 23 DNA-Sequenzabweichungen in der Keimbahn von 24/46 Familien und 4 somatische Mutationen in 3 Tumoren festgestellt. Bei 15 Mutationen handelt es sich um neue, bislang noch nicht beschriebene genetische Veränderungen. Keine dieser neuen genetischen Varianten konnte in 100 Allelen gesunder Individuen nachgewiesen werden. Von 2, in Introns lokalisierten Varianten (MLH1 c.589-10T > A; MSH2 c.367-1G > A), konnten wir die Auswirkung auf die mRNA zeigen. In beiden Fällen entstanden neue Spleiß-Stellen, welche die Regulären ersetzten. Keimbahnmutationen traten in 44,8% der Amsterdam-Familien und in 35,3% der Bethesda-Patienten auf. Die Korrelation zwischen dem Nachweis einer pathogenen Keimbahnmutation und einer Mikrosatelliteninstabilität in der Tumor-DNA war hoch signifikant (p = 0,007). Diese Studie stellt den ersten umfassenden Bericht über Mutationen in Mismatch-Reparatur-Genen bei österreichischen Patienten mit erblichem nicht-polypösem Kolonkarzinom-Syndrom dar.

TP53 germline mutation may affect response to anticancer treatments: analysis of an intensively treated Li–Fraumeni family

Li–Fraumeni syndrome (LFS) is a rare autosomal dominant inherited disorder associated with the occurrence of a wide spectrum of early-onset malignancies, the most prevalent being breast cancer and sarcoma. The presence of TP53 germline mutations in the majority of LFS patients suggests a genetic basis for the cancer predisposition. No special recommendations for the treatment of LFS patients have been made to date, except that of minimizing radiation. We hypothesized that TP53 germline mutations may be associated not only with cancer predisposition, but also with lack of response to chemo- and radiotherapy. Here, we present an Austrian LFS family whose members were intensively treated with chemo- and radiotherapy due to cancers that occurred at a predominantly young age, including eight breast cancers in six patients. Material from seven family members was screened for p53 mutation by Sanger sequencing and immunohistochemistry. A rare missense mutation in the tetramerization domain of exon 10 of the TP53 gene was found to segregate with malignant disease in this family. Lack of response to various chemotherapies and radiotherapy could be ascertained by histopathology of surgical specimens after neoadjuvant treatment, by cancer relapse occurring while receiving adjuvant systemic treatment and by the occurrence of second primaries in areas of adjuvant radiation. Our observations suggest that current standards of cancer treatment may not be valid for patients with LFS. In patients with TP53 germline mutation, cytotoxic treatment may bear not only the risk of tumor induction but also the risk of treatment failure.