Prognostic value of PCNA and cytokeratins for radiation therapy of oral squamous cell carcinoma

PCNA and anti-apoptotic Mcl-1 proteins predict disease-free survival in oral cancer patients treated with definitive radiotherapy

At our laboratory, we recently observed cell cycle and apoptosis-related proteins Myeloid Cell Leukemia-1 (Mcl-1) and Proliferating Cell Nuclear Antigen (PCNA) to be altered in oral tumours/cell lines. The present study aimed to evaluate the above proteins for predicting response and outcome in oral cancer patients treated with definitive radiotherapy. Pre-treatment oral cancer biopsy samples from 39 patients were examined for Mcl-1 and PCNA proteins using immunohistochemistry and correlated with clinico-pathological variables using disease-free survival (DFS) as the primary endpoint. We observed high expression of Mcl-1 in older versus younger patients (p=0.013) and in tobacco chewers+/-alcohol versus smokers+/-alcohol (p=0.037); and PCNA in node-positive versus node-negative tumours (p=0.037). On univariate analysis, high PCNA (p=0.007), Mcl-1 (p=0.050), node positivity (p=0.040) and co-expression of PCNA and Mcl-1 (p=0.008), had a significant impact on DFS. On multivariate analysis, low PCNA/Mcl-1 (p=0.006) co-expressing tumours were associated with improved DFS. Thus our study suggests that in patients undergoing primary radiotherapy, PCNA could be of potential predictive value to identify patients with risk of nodal metastases and in combination with Mcl-1 may have potential prognostic value to differentiate patients with poor DFS. These markers may be used for future trial patients requiring radiotherapy for their treatment.

Proliferative activity and loss of function of tumour suppressor genes as 'biomarkers' in diagnosis and prognosis of benign and preneoplastic oral lesions and oral squamous cell carcinoma

Oral cancer is a disease of the elderly and is closely connected with cigarette smoking and alcohol consumption. Since the successful introduction of multidisciplinary treatment, the survival rate has not changed. Because of the high mortality and potentially disfiguring treatment, today's efforts are aimed at eliminating risk factors, chemoprophylaxis, improvement in diagnostic procedures, and understanding of the genetic mechanisms of oral carcinogenesis. Immunohistochemical and molecular biology analysis of biopsy tissue and cell lines of preneoplastic and neoplastic lesions that originate from the oral mucosa have shown that alterations in tumour suppressor genes such as p53 and Rb gene may have an important role in oral carcinogenesis and may be potentially useful prognostic 'biomarkers' in oral carcinogenesis. Statistical analysis of immunohistochemical data from 216 patients did not identify significant or consistent differences of p53, MDM2, or RB expression with respect to stage of disease, malignant transformation, metastatic node involvement, recurrence, or survival. Nevertheless, p53 overexpression seems to correlate strongly with histological progression of the disease, which confirms the importance of p53 alterations in oral carcinogenesis. Overexpression of p53 is usually found in the less differentiated proliferating cells in benign and malignant oral lesions. Assessment of the proliferating activity is possible by immunohistochemical staining with monoclonal antibodies against proliferating nuclear antigen and Ki-67. Statistical analysis shows that overexpression of p53 combined with high proliferative activity predicts a less favourable course of disease in oral squamous cell carcinoma.

Nodal CT density and total tumor volume as prognostic factors after radiation therapy of stage III/IV head and neck cancer

PURPOSE

To determine whether the immunohistochemical expression of proliferation-associated antigens (proliferating cell nuclear antigen, MIB1) and the nuclear p53 reactivity in addition to total tumor volume, nodal CT density and T and N category are predictive for overall survival and locoregional tumor control in patients with squamous cell carcinoma of the head and neck region.

MATERIALS AND METHODS

Between October 1989 and September 1993, 87 patients with biopsy proven head and neck cancer were randomly allocated to receive radiation alone or simultaneous radiation and chemotherapy as part of a multicenter trial with a total of 298 randomized patients. There were only inoperable lesions in UICC (1992) stage III (8%) and IV (92%). Radiotherapy was delivered with 180 cGy twice daily up to a total dose of 7020 cGy in 51 days. Three cycles of 2340 cGy each were separated by a rest period of 11 days. Chemotherapy consisted of cis-DDP, 5-fluorouracil and leucovorin and was repeated on days 22 and 44. Routinely-processed paraffin-embedded sections were stained using monoclonal antibodies for detection of proliferation-associated antigens (MIB1 and PCNA) and p53 oncoprotein to determine the labeling index (LI). In addition, the total tumor volume and the percentage of necrosis were measured using CT data. The median follow-up was 3.9 years (range 1.9-5.0 years).

RESULTS

The overall survival and locoregional control for all 87 patients were 34 and 39% at 3 years, respectively. The addition of chemotherapy resulted in a better overall survival (27 versus 47%, P = 0.03) but did not influence locoregional control (31 versus 47%, P = 0.08). In univariate analysis, nodal CT density (P < 0.0001), total tumor volume (P < 0.0001), age (P = 0.001) and the MIB1-LI (P = 0.04) had a significant impact on overall survival. However, in the final Cox model only the nodal CT density (P = 0.0003) and age (P = 0.05) were independent prognostic factors for survival and only the nodal CT density (P = 0.0006) was an independent prognostic factor for locoregional control. The expression of the p53 oncoprotein was not found to have a clear predictive value.

CONCLUSION

Nodal CT density, total tumor volume and age will remain the relevant prognostic factors in stage III/IV head and neck cancer.

Sphincter preservation with chemoradiation in anal canal carcinoma: abdominoperineal resection in selected cases?

PURPOSE

This study contained herein assessed long-term results, toxicity, and prognostic variables following combined modality therapy of patients with International Union Against (Cancer Classification T1-4, N0-3, M0 squamous-cell carcinoma of the anal canal.

PATIENTS AND METHODS

Between 1985 and 1996, 62 patients completed treatment with combined modality therapy. A median total dose of 50 Gy was given to the primary, perirectal, presacral, and inguinal nodes followed by a local boost in selected cases. 5-Fluorouracil was scheduled as a continuous infusion of 1,000 mg/m2 per 24 hours on days 1 to 5 and 29 to 33 and mitomycin C as a bolus of 10 mg/m2 on days 1 and 29. Routinely processed paraffin-embedded sections were stained using monoclonal antibodies for detection of proliferating cell nuclear antigen and MIB1 (Ki-67) antigen to determine the labeling index. In addition, DNA ploidy was assessed after Feulgen staining.

RESULTS

Actuarial cancer-related survival, no evidence of disease survival, and colostomy-free survival rates at five years were 81, 76, and 86 percent, respectively. In univariate analysis, T category (T1/2 vs. T3/4) was predictive for no evidence of disease survival (87 vs. 59 percent; P = 0.03) and colostomy-free survival (94 vs. 73 percent; P = 0.05). N category (N0 vs. N1-3) influenced actuarial cancer-related survival (85 vs. 58 percent; P = 0.002) and no evidence of disease survival (80 vs. 53 percent; P = 0.02). A higher proliferative potential as measured by the MIB1 labeling index was associated with a better colostomy-free survival (90 vs. 50 percent; P = 0.04). In multivariate analysis, actuarial cancer-related survival was only influenced by the N category (P = 0.03) and no evidence of disease survival by N category (P = 0.03) and mitomycin C dose (P = 0.04). Salvage abdominoperineal resection achieved long-term control in only four of seven patients with local failures.

CONCLUSION

Treatment with a combination of radiotherapy and chemotherapy is safe and effective for patients with anal canal carcinoma. Abdominoperineal resection is indicated as a salvage procedure in nonresponding and recurrent lesions and may be of benefit in a small subgroup of patients with poor prognostic factors.

High PCNA index in meningiomas resistant to radiation therapy

PURPOSE

Meningiomas are common intracranial tumors, often well controlled with surgical resection alone. While the efficacy of radiation therapy in improving local control and progression-free survival is well documented, prognostic data substantiate factors that are predictive of poor local control following definitive radiation therapy. PCNA is a DNA polymerase expressed at the highest levels in the S-phase, the most resistant portion of the cell cycle to ionizing radiation in vitro. We investigated the possible correlation between the levels of PCNA expression and the clinical outcome of patients treated with definitive radiation therapy.

METHODS AND MATERIALS

Archival tissue was collected from 33 cases of meningioma treated at our institution for definitive radiation therapy between 1970 and 1990. Age-matched normal meningeal tissue and asymptomatic meningiomas removed at autopsy served as tissue controls. A standard ABC immumoperoxidase technique employing antibodies to PCNA, PC-10 (Dako, California) was used to stain specimen slides for PCNA. PCNA index was defined as the number of positive nuclei per 10 high-power fields at 400x magnification. Two independent observers scored the slides without prior knowledge of the cases at hand.

RESULTS

Patients with high PCNA index were less likely to be controlled by therapeutic radiation (p < 0.001, Kaplan-Meier). All patients with a PCNA index greater that 25 failed radiation therapy. Using multivariate analyses, malignant (but not atypical), histology and PCNA index were significant predictors of progression following radiation therapy (p < 0.05, log rank).

CONCLUSION

PCNA index may be a useful adjunct to more standard histopathologic criteria in the determination of meningioma local control and progression-free survival following therapeutic irradiation. Data on a more expanded population evaluated on a prospective basis will be needed before such criteria are routinely employed in the clinical setting.

Mean nuclear area and chromosomal DNA content of squamous cell carcinomas of the oral cavity using computerized image analysis

Morphometric measurements of nuclei may be of prognostic value in some cancers. In this present study we have evaluated the mean nuclear area (MNA) of 50 squamous cell carcinomas of the oral cavity (SCCOC) using computerized image analysis. Since chromosomal DNA content is a reflection of the DNA content in the nucleus, we have evaluated the relationship between MNA and chromosomal DNA. Thirteen tumours had a MNA greater than 49.9 microns2 and 37 had a MNA less than this. Six tumours were classified as hypodiploid, 29 as diploid and 15 as aneuploid. There were 44 node-negative patients and six node-positive. When comparing MNA in these groups, 50 per cent of node-positive patients had a larger MNA whilst only 20 per cent of the node-negative group had a large MNA. The correlation coefficient between MNA and DNA indices was r = 0.75. The greater nuclear size is possibly a reflection of a more aggressive tumour biology in the node-positive patients. We conclude that a large MNA may be a marker of aggressive tumour biology in this group. In the future, we aim to evaluate the prognostic significance of MNA in patients with SCCOC.