DNA repair biomarkers XPF and phospho-MAPKAP kinase 2 correlate with clinical outcome in advanced head and neck cancer.

BACKGROUND: Induction chemotherapy is a common therapeutic option for patients with locoregionally-advanced head and neck cancer (HNC), but it remains unclear which patients will benefit. In this study, we searched for biomarkers predicting the response of patients with locoregionally-advanced HNC to induction chemotherapy by evaluating the expression pattern of DNA repair proteins. METHODS: Expression of a panel of DNA-repair proteins in formalin-fixed paraffin embedded specimens from a cohort of 37 HNC patients undergoing platinum-based induction chemotherapy prior to definitive chemoradiation were analyzed using quantitative immunohistochemistry. RESULTS: We found that XPF (an ERCC1 binding partner) and phospho-MAPKAP Kinase 2 (pMK2) are novel biomarkers for HNSCC patients undergoing platinum-based induction chemotherapy. Low XPF expression in HNSCC patients is associated with better response to induction chemoradiotherapy, while high XPF expression correlates with a worse response (p = 0.02). Furthermore, low pMK2 expression was found to correlate significantly with overall survival after induction plus chemoradiation therapy (p = 0.01), suggesting that pMK2 may relate to chemoradiation therapy. CONCLUSIONS: We identified XPF and pMK2 as novel DNA-repair biomarkers for locoregionally-advanced HNC patients undergoing platinum-based induction chemotherapy prior to definitive chemoradiation. Our study provides insights for the use of DNA repair biomarkers in personalized diagnostics strategies. Further validation in a larger cohort is indicated.

Utilization of fluorescence in situ hybridization with cytokeratin discriminators in TOP2A assessment of chemotherapy-treated patients with breast cancer.

Tumor biomarkers increasingly provide information for predicting outcomes with chemotherapeutic regimens (personalized medicine). Topo2A is a DNA helicase targeted by anthracyclines, cytotoxic therapeutics used in both adjuvant and palliative treatments of breast cancer. TOP2A gene amplification/deletion is implicated in response to anthracycline-based chemotherapy. We describe an approach for analyzing formalin-fixed, paraffin-embedded breast tumors on tissue microarrays with TOP2A fluorescence in situ hybridization coupled with cytokeratin immunofluorescence to target tumor cells. Stained tissue from patient specimens was imaged and analyzed using Metafer/Metacyte (Metasystems, Waltham, MA, USA), including customized image classifiers. TOP2A/CEN17 ratios of 2.0 or greater (amplified) and 0.8 or less (deleted) were observed for 10.0% and 6.1% of the patients, respectively. Patient outcomes for adjuvant chemotherapy (cyclophosphamide-epirubicin-fluorouracil, cyclophosphamide-methotrexate-fluorouracil, no chemotherapy) were evaluated. No statistical significance was achieved for clinical end points regarding TOP2A status in anthracycline-treated patients. However, patients with TOP2A aberrations receiving methotrexate-based therapy exhibited a significant decrease in 5-year distant disease-free survival and breast cancer-specific overall survival, especially for patients with TOP2A deletions (disease-free survival: hazard ratio, 5.31 [P = .001], and breast cancer-specific overall survival: hazard ratio, 6.45 [P ≤ .001]). No significant differences were seen in patients included in the no-chemotherapy group. Topo2A protein levels were assessed by immunohistochemistry with no correlative statistical relevance to immunofluorescence/fluorescence in situ hybridization-based prognosis for cyclophosphamide-epirubicin-fluorouracil or cyclophosphamide-methotrexate-fluorouracil groups. Interestingly, aberrant (under)expressing patients in the no-chemotherapy group exhibited better 5-year distant disease-free survival (hazard ratio, 0.39; P = .004), trending toward more favorable breast cancer-specific overall survival (hazard ratio, 0.61; P = .11). Our results indicate a strategy by which fluorescence in situ hybridization scoring targeted to cytokeratin-positive tumor cells may provide a tool for added precision and efficiency in TOP2A evaluation from tumor tissue.