Molecular and cellular biomarkers for field cancerization and multistep process in head and neck tumorigenesis

One way to explain the development of head and neck cancer is through the theories of field cancerization, i.e., the exposure of an entire field of tissue to repeated carcinogenic insult, and multistep process, i.e., development of multiple cancers in a predisposed filed through a series of recognizable stages. Recent molecular genetic studies of histologically normal and premalignant epithelia of high-risk subjects and studies of malignant tumors in aerodigestive tract epithelia have identified a continuum of accumulated specific genetic alterations that possibly occur during the clonal evolution of tumors, namely, during the multistep process. Second primary or multiple primary tumors arise in the same fields as independent clones, with similar but unique molecular genetic and/or cellular alterations. Consequently, the assessment of these genetic and phenotypic alterations has been integrated into clinical chemoprevention trials in an effort to identify biomarkers that are also risk predictors and intermediate end points. This review covers candidate biomarkers of the processes of field cancerization and multistep tumor development in aerodigestive tract epithelia, including general and specific genetic markers, proliferation markers, and squamous differentiation markers.

Phase II study of topotecan in patients with advanced non-small-cell lung cancer previously untreated with chemotherapy

PURPOSE

This study was designed to assess the anti-tumor activity of topotecan (TPT) in patients with advanced non-small-cell lung cancer (NSCLC) previously untreated with chemotherapy.

PATIENTS AND METHODS

Patients with stage IIIB or IV NSCLC with measurable disease in nonradiated fields were eligible. Other eligibility criteria were Zubrod performance status (PS) < or = 2 and adequate renal and liver function. TPT was administered at a dose of 1.5 mg/m2/d for 5 days over 30 minutes every 21 days. Of 48 registered patients, 40 were fully assessable. Nineteen patients had adenocarcinoma (AD), 14 squamous carcinoma (SCC), and seven poorly differentiated carcinoma.

RESULTS

Six patients (15%) achieved a partial remission (PR) (durations: 8, 14, 18, 28, 56, and 61 weeks) and four patients a minor response; 10 patients had stable disease and 20 patients progressive disease. The PR rate was 36% (five of 14 patients) in patients with SCC versus 4% (one of 26 patients) in those with other histologies (P = .014). The overall median survival time was 38 weeks and 30% of patients were alive at 1 year. Grade 3 to 4 granulocytopenia and thrombocytopenia occurred after 76% and 10% of courses administered, respectively. No grade 3 to 4 nonhematologic toxicities were observed. Grade 1 or 2 nonhematologic toxicities consisted of nausea (46% and 5%), vomiting (31% and 7%), and fatigue (53% and 16%).

CONCLUSION

TPT at the dose and schedule used has moderate antitumor activity in NSCLC; its activity is mostly limited to patients with SCC. TPT is well tolerated, with myelosuppression of short duration being the most common and limiting toxicity.

Detection of chromosome instability of tissue fields at risk: in situ hybridization

Many human tumors are thought to develop along a multistep pathway in tissues that have encountered long periods of carcinogen exposure and thus have accumulated genetic hits in functional targets relevant to tumor evolution. The cumulative degree of genetic change is dependent on both exogenous (e.g., degree of carcinogen exposure) and endogenous factors (e.g., metabolism of procarcinogens, repair or misrepair capacity, proliferation properties of the tissue, capability of damaged cells to survive). Thus one approach to risk estimation is to measure the accumulated amount of genetic damage in a target tissue at risk for tumor development. Since one cannot predict the exact site of the future tumor, the risk assay must detect a generalized ongoing process of genetic instability from small, random biopsies. The technique of chromosome in situ hybridization involves the use of chromosome- or region-specific probes and provides an ability to directly visualize genetic change (e.g., random or clonal chromosome polysomy and monosomy) on thin tissue sections (where tissue architecture is maintained) or exfoliated cells. Analyses of normal and premalignant lesions adjacent to tumors (e.g., head and neck, lung, bladder, cervix, breast) have demonstrated that chromosome instability can be detected in the field of the tumor (i.e., in normal and premalignant cells in a tissue at 100% risk of tumor development) and the degree of chromosome instability increases with the degree of histologic progression toward cancer. Analyses of premalignant lesions (e.g., oral leukoplakia and erythroplakia from individuals at risk for aerodigestive tract cancer) by chromosome in situ hybridization have uncovered varying degrees of chromosome instability. However, approximately half of those individuals who showed a high degree of chromosome instability in biopsies subsequently developed aerodigestive tract cancer. Of interest, half of these tumors have developed away from the biopsied site, suggesting that the detection of a chromosome instability process in one aspect of the tissue might yield risk information for the total tissue field. These studies also suggest that chromosome in situ hybridization might be useful for identifying individuals with high tumor risk who might benefit from chemopreventive intervention.

Prospective study of combination chemotherapy with cyclophosphamide, doxorubicin, and cisplatin for unresectable or metastatic malignant pleural mesothelioma

BACKGROUND

This study was designed to determine the efficacy and side effects of a combination of cyclophosphamide (C), doxorubicin (D), and cisplatin (P) in patients with inoperable, unresectable, or metastatic malignant pleural mesothelioma.

METHODS

Twenty-three patients with unresectable or metastatic malignant pleural mesothelioma were entered onto the study. The median age was 62 years (range, 42-74 years); there were 20 males and 3 females; the median performance status was 1 (Zubrod's scale). The histologic types included epithelial (14 patients), sarcomatoid (4 patients), unclassified (4 patients), and mixed type (1 patient). Twenty patients were known to have been exposed to asbestos and 3 were not. All patients were treated with the following starting dose of chemotherapy: a cycle comprised of C, 500 mg/m2 intravenously, day 1; D, 50 mg/m2 intravenously, day 1; and P, 80 mg/m2 intravenously, day 1 every 3 weeks. The cisplatin dose was reduced to 50 mg/m2 for the subsequent courses. For the assessment of tumor response, all patients had computed tomography scans of the chest after each three cycles of chemotherapy.

RESULTS

Overall, 7 of 23 patients (30%) had partial responses (durations of responses [weeks]: 158+, 91+, 70+, 41+, 40, 39, 25), three had minor responses, and 14 had stable or progressive disease. One partial responder later underwent surgical resection and no viable tumors cells were found in the pathologic specimen. All patients have stopped treatment, and eight are still alive. The most common side effect was granulocytopenia (grade 4, 52%; grade 3, 17%). Other hematologic side effects were modest. Nonhematologic side effects included mild to moderate nausea and vomiting, neutropenic fever (three patients), peripheral neuropathy (one patient), and congestive heart failure (one patient). The overall median duration of survival was 60 weeks.

CONCLUSION

Combination chemotherapy with CDP was well tolerated and had significant activity against unresectable or metastatic malignant pleural mesothelioma. The median duration of responses was 60 weeks; however, the survival rate was far from satisfactory. Continued development of new approaches including the biologic understanding of tumor development and testing new agents is warranted.

Evaluation of cognitive function in patients with limited small cell lung cancer prior to and shortly following prophylactic cranial irradiation

PURPOSE

Cognitive deficits after treatment for small cell lung cancer (SCLC) have been attributed to prophylactic cranial irradiation (PCI). A prospective study of neuropsychological function was undertaken to document the evolution and magnitude of neuropsychologic deficits.

METHODS AND MATERIALS

Thirty patients with limited stage SCLC who responded well (29 complete response (CR), 1 partial response (PR)) to combination chemotherapy plus thoracic irradiation or resection were studied with neuropsychological tests in the cognitive domains of intelligence, frontal lobe function, language, memory, visual-perception, and motor dexterity prior to a planned course of PCI. Nine patients had a neurologic history that could influence testing.

RESULTS

An unexpected 97% (29 out 30) of patients had evidence of cognitive dysfunction prior to PCI. The most frequent impairment was verbal memory, followed by frontal lobe dysfunction, and fine motor incoordination. Of the patients with no prior neurologic or substance abuse history, 20 out of 21 (95%) had impairments on neuropsychological assessment. This neurologically normal group was just as impaired as the group with such a history with respect to delayed verbal memory and frontal lobe executive function. Eleven patients had neuropsychological testing 6 to 20 months after PCI; no significant differences were found from their pretreatment tests.

CONCLUSIONS

A high proportion of neurologically normal patients was limited SCLC and favorable responses to combination chemotherapy have specific cognitive deficits before receiving PCI. Short-term (6 to 20 months) observations after PCI have shown no significant deterioration.

Phase II study of docetaxel for advanced or metastatic platinum-refractory non-small-cell lung cancer

PURPOSE

We conducted a phase II study to determine the response to and toxicity of docetaxel (Taxotere; Rhône-Poulenc Rorer Pharmaceuticals, Inc, Collegeville, PA) in patients with advanced non-small-cell lung cancer refractory to prior platinum-containing chemotherapy (PCC) regimens.

PATIENTS AND METHODS

Forty-four patients with stage IIIb or IV platinum-refractory non-small-cell lung cancer were treated with 100 mg/m2 of docetaxel intravenously over 1 hour every 3 weeks. The responses of 42 of 44 patients were assessable. Most patients had a Zubrod performance status of 1; the predominant histologic type was adenocarcinoma (61%), and 91% of patients had stage IV disease.

RESULTS

Nine of 42 assessable patients (21%) achieved a partial response to treatment. The median response duration (from response to progression) was 17 weeks, and the projected median survival duration of all patients is 42 weeks (51 weeks for adenocarcinoma and 22 weeks for nonadenocarcinoma). Grade 3/4 neutropenia occurred in 85% of patients and was associated with fever that required intravenous antibiotics in 16% of patients (3% of cycles). Other acute side effects included easily treated hypersensitivity reactions and dermatitis. Cumulative side effects included fluid retention and neuropathy.

CONCLUSION

Docetaxel administered at 100 mg/m2 intravenously every 3 weeks has notable activity against platinum-refractory non-small-cell lung cancer, with a 21% major response rate. Primary side effects were neutropenia, hypersensitivity, and fluid retention.

Interdigitating versus concurrent chemotherapy and radiotherapy for limited small cell lung cancer

PURPOSE

Sequencing and timing of chemotherapy and radiotherapy for limited small-cell lung cancer (LSCLC) was studied in two consecutive trials.

METHODS AND MATERIALS

In the interdigitating (IDG) trial, three cycles of COPE (cyclophosphamide 750 mg/M2 i.v. Day 1, vincristine 2 mg i.v. Day 8, cisplatin [DDP] 20 mg/M2 Days 1-3, etoposide 100 mg/M2 i.v. Days 1-3), were followed by thoracic radiation therapy (1.5 Gy bid 5-6 h apart, repeated twice at 3-week intervals) to give 45 Gy in 9 weeks; COPE was given during the intervals and for two more cycles. Operable patients had thoracotomy followed by IDG. Prophylactic cranial irradiation (PCI), 2.0 Gy x 15 fractions with a total dose of 30 Gy in 3 weeks, was given to the complete responders (CR) after completion of chemotherapy. In the concurrent (CON) trial, patients received DDP 60 mg/M2 i.v. Day 1, and etoposide 120 mg/M2 i.v. Days 1-3 for four cycles, every 3 weeks, and concurrent thoracic radiation therapy to 45 Gy with either 1.8 Gy daily, for 5 weeks or 1.5 Gy bid for 3 weeks. Prophylactic cranial irradiation (PCI) was given to the complete responders, 2.5 Gy daily for 2 weeks (25 Gy) (approximately 3 months after the initiation of treatment).

RESULTS

The IDG group had 28 evaluable patients with median follow-up of 17.5 months. The CON group had 33 evaluable patients with median follow-up of 21 months. Overall survival rates for IDG patients were 79% at 1 year, 39% at 2 years, 30% at 3 years, and 27% at 4 years compared to 93%, 70%, 51%, and 46%, respectively, for the patients treated with CON (p = 0.01). Loco-regional recurrence (44%) and distant metastasis (48%) was more frequent as the first site of failure in the IDG group compared to the CON group (30% and 30%, respectively). Brain metastases constituted 30% of first metastases with IDG compared to none with CON. Esophagitis was significantly greater with CON. Hematologic and pulmonary toxicity were similar with IDG and CON. One death due to infection was seen in each treatment group.

CONCLUSION

Concurrent chemoradiotherapy appears to be more effective than IDG. Earlier administration of PCI with concurrent chemotherapy and thoracic irradiation may reduce the risk of brain metastasis.

Three-dimensional kinematic analysis of baseball pitching in acceleration phase

To examine the relationships of pitching performance to maximum external rotation of the shoulder and to time in the acceleration phase, 3 male baseball pitchers were tested using three-dimensional cinematography. Analysis indicated that increasing maximum external rotation of the shoulder at the very beginning of the acceleration phase would help to generate a higher pitching ball velocity since a greater linear and angular displacement could be used to accelerate the throwing forearm. Slowing the wrist action just before ball-release may be a key technique to increasing pitching velocity of the ball.

p53 and retinoid chemoprevention of oral carcinogenesis

We studied p53 protein's pattern of expression, association with retinoid response or resistance, and modulation by retinoid intervention in oral premalignancy. These p53 analyses were included in a prospective trial of the retinoid isotretinoin (1.5 mg/kg/day for 3 months) in 40 patients (45 oral premalignant lesions). Seven nonsmoking subjects (eight oral biopsies) were included as a control. Protein levels of p53 were determined separately for the whole epithelium and the basal, parabasal, and superficial layers. A wide range of accumulated p53 protein levels occurred in 40 (89%) of 45 lesions in basal and parabasal but not superficial layers. No p53 protein was detected in any normal controls. Accumulation of p53 increased in direct association with histological grade (P = 0.0004). An inverse relationship occurred between the levels of accumulated p53 protein and response to isotretinoin (P = 0.006). High-dose isotretinoin did not modulate accumulated p53 protein expression.

Biomarkers in upper aerodigestive tract tumorigenesis: a review

Because therapeutic efforts such as surgery, radiotherapy, and chemotherapy have only marginally improved the 5-year survival rate from cancers of the upper aerodigestive tract (including head and neck and lung cancers) over the past 2 decades, chemoprevention has become an important strategy in reducing the rates of incidence and mortality of these cancers. However, chemoprevention trials have been hampered by serious feasibility problems; they require large numbers of subjects and long-term follow-up for accurate determination of cancer incidence and they are very costly. Because the use of intermediate end points would reduce the duration and costs of these studies, biomarkers that could serve as such end points have recently become a subject of great interest. With the strengthening of the assumption that tumorigenesis is a multistep process of transformation from normal tissues to malignant lesions, there has been a great effort to examine each of these steps for genetic and/or phenotypic alterations that might be candidates for such biomarkers. These candidates include genomic markers, certain specific gene alterations, such as tumor suppressor genes, oncogenes, growth factors and their receptors, proliferation markers, and differentiation markers. In this review, we describe several genomic markers, including micronuclei, chromosomal alterations, and specific genetic markers, e.g., the ras gene family, erb B1, int-2/hst-1, and p53 tumor suppressor gene. We also review the proliferation markers, including proliferating cell nuclear antigen, and squamous cell differentiation markers, including keratins, involucrin, and transglutaminase 1. These biomarker candidates have the potential to be important adjuncts to the development of new chemopreventive agents and to the rational design of future intervention trials. However, we can not overemphasize that these markers need to be validated in clinical trials; only then can they replace cancer incidence as the sole end point for chemoprevention trials.

Differential expression of nuclear retinoid receptors in normal, premalignant, and malignant head and neck tissues

Retinoids reverse premalignant lesions and inhibit the development of second primary cancers in patients with upper aerodigestive tract cancers. It is thought that these effects result from the ability of retinoids to restore normal cell growth and differentiation. Since nuclear retinoid receptors (RARs and RXRs) are the ultimate mediators of retinoid actions, alterations in their expression could lead to cancer development. To determine whether the expression of the mRNAs of the receptors is related to the development of head and neck squamous cell carcinoma (HNSCC), we used digoxigenin-labeled antisense riboprobes of RAR-alpha, RAR-beta, RAR-gamma, RXR-alpha, and RXR-beta for in situ hybridization to histological sections of specimens from 7 normal volunteers and 31 HNSCC patients. All 31 tissue specimens contained carcinomas, 16 also contained dysplastic lesions, 22 also contained hyperplastic lesions, 17 also contained adjacent normal tissue, and 6 contained all 4 types of tissue. All specimens from normal volunteers expressed the 5 receptors. Similar levels of RAR-gamma and RXR-alpha and RXR-beta mRNAs were detected in most of the adjacent normal, hyperplastic, dysplastic, and malignant tissues. RAR-alpha mRNA was detected in 94% of adjacent normal tissues and hyperplastic tissues, in 87% of dysplasias, and in 77% of HNSCCs. In contrast, RAR-beta mRNA was detected in about 70% of adjacent normal and hyperplastic lesions, and its expression decreased further to 56% of dysplastic lesions and to 35% of HNSCCs. The difference in RAR-beta level in carcinoma and adjacent normal tissues was significant (P < 0.05). These results indicate that the decreased expression of RAR-beta may be associated with HNSCC development.

Dysregulation of epidermal growth factor receptor expression in premalignant lesions during head and neck tumorigenesis

The development of head and neck cancer, believed to result from field cancerization and a multistep process of tumorigenesis, is often associated with an accumulation of genotypic and phenotypic alterations. The phenotypic changes could be the result of dysregulation of growth control genes such as epidermal growth factor receptor (EGFR). With the goal of identifying a potential biomarker of the multistep process of tumorigensis, we studied specimens of 36 head and neck squamous cell carcinomas from 5 different sites that contained normal epithelia and/or premalignant lesions adjacent to the tumors. Almost all of the individuals from whom these specimens were obtained had been exposed to first-hand smoking and/or alcohol consumption. Using a monoclonal anti-EGFR antibody for immunohistochemical analysis on paraffin-embedded sections with attached 886 cells for internal control, the levels of EGFR expression were assessed by image analysis. The relative staining intensity of EGFR in normal epithelia adjacent to tumors was 2-fold higher than that in normal control epithelium (P = 0.021), suggesting that, even in histologically normal epithelium, EGFR was already up-regulated in tissues surrounding tumors. These findings supported the theory of field cancerization in head and neck tumorigenesis. As tissue progressed from normal tissue adjacent to tumor to hyperplasia and to dysplasia, EGFR expression remained elevated. However, in the step from dysplasia to squamous cell carcinoma, EGFR expression was further and dramatically up-regulated (P = 0.01). Therefore, these results indicate that EGFR dysregulation happens in two steps, the moderate up-regulation of EGFR expression in normal epithelium adjacent to tumor and the further up-regulation of EGFR expression in the change from dysplasia to squamous cell carcinoma. In summary, the studies presented here indicate that EGFR dysregulation might be a useful marker for identifying individuals at risk of tumor development and an intermediate end point in chemoprevention trials.

Phase II study of docetaxel for recurrent or metastatic non-small-cell lung cancer

PURPOSE

We conducted a phase II study to determine the response and toxicity of docetaxel (Taxotere; Rhône-Poulenc Rorer Pharmaceuticals, Inc, Collegeville, PA) in chemotherapy-naive patients with advanced non-small-cell lung cancer.

PATIENTS AND METHODS

We treated 41 chemotherapy-naive patients who had stage IIIb or IV non-small-cell lung cancer with 100 mg/m2 of docetaxel intravenously over 1 hour every 3 weeks. Responses were assessed after every one to two treatment courses. Responses of 39 of 41 patients were assessable. The patient's median age was 63 years; 90% of patients had a Zubrod performance status of 0 or 1. The predominant histology was adenocarcinoma (54%), and 90% of patients had stage IV disease.

RESULTS

Thirteen patients (33%) achieved a partial response to treatment, and the median response duration was 14 weeks. Grade 3 or 4 neutropenia occurred in 97% of patient; this was usually of brief duration and was associated with serious infection in 17% of patients. Other acute toxic effects included easily treated hypersensitivity reactions (36% of patients) and dermatitis (74%). We also observed fluid retention (with peripheral edema or pleural effusion or both) in 54% of patients. This was a cumulative side effect that generally occurred late in treatment.

CONCLUSION

Docetaxel administered at 100 mg/m2 intravenously every 3 weeks has significant activity against non-small-cell lung cancer, with a 33% major response rate. Primary toxicities were neutropenia, hypersensitivity, and fluid retention.

Biomarkers in chemoprevention for upper aerodigestive tract tumors

A chemopreventive approach to cancers of the upper aerodigestive tract (including those of head and neck and lung) to reduce the incidence and mortality rates for these cancers has become an important strategy because therapies such as surgery, radiation, and chemotherapy have only marginally improved the five-year survival rate over the last two decades. However, chemopreventive trials have been hampered by serious feasibility problems, including high cost, the requirement of large numbers of patients, and long-term follow-up necessary to determine cancer incidence, which served as the study end point. Thus, the use of biomarkers, the identification of which would serve as an intermediate end point of the study has recently emerged as a subject of great interest. To try to understand the process of tumorigenesis from normal tissues through the premalignant tissue stage to malignant lesions, there has recently been a search for genetic and/or phenotypic changes that qualify as candidates for biomarkers. These candidates include genomic markers, certain specific genetic markers (such as oncogenes, growth factors and their receptors, and tumor suppressor genes), cell proliferation markers, and cell differentiation markers. This review covers genomic markers (including micronuclei and specific chromosomal alterations) and specific genetic markers (such as the ras gene family, the myc family, erb B1, int-2/hst-1, and the p53 tumor suppressor gene). As a consequence of genetic alteration, we also reviewed cell proliferation markers such as proliferating cell nuclei antigen (PCNA) and the squamous cell differentiations markers, including keratins, involucrin, and transglutaminase 1. These biomarker candidates are important adjuncts to the development of the new chemopreventive agents and to the rational design of future intervention trials. However, it should be emphasized that these biomarkers must first be validated in clinical trials; only then can they replace cancer incidence as the sole end point in chemoprevention trials.

Thymoma. A retrospective study of 87 cases

BACKGROUND

The authors retrospectively analyzed 87 patients with malignant thymoma treated at M.D. Anderson Cancer Center between 1951 and 1990. The analysis examined the clinical stages, histologic types, and treatment modalities and attempted to determine if chemotherapy had an impact on survival.

METHODS

The patients were divided into three groups by their year of treatment and treatment modality. Patients treated between 1951 and 1975 were in Group I; patients treated between 1976 and 1980 were in Group II; and patients treated between 1981 and 1990 were in Group III. Most of the patients (18 [72%] in Group I; 16 [62%] in Group II; and 18 [50%] in Group III) had surgical resection alone or with radiotherapy. Patients with advanced-stage disease in Group I received single-agent chemotherapy, whereas patients with advanced-stage disease in Group II received a different, combination chemotherapy regimen, and those in Group III were treated primarily with cisplatin- and doxorubicin-based combination chemotherapy, e.g., the cyclophosphamide doxorubicin, and cisplatin with or without prednisone. The 17 patients treated with cisplatin with or without prednisone were separately evaluated for survival according to their response.

RESULTS

Twenty-eight patients (5 [20%] in Group I; 6 [23%] in Group II; and 17 [47%] in Group III) received chemotherapy alone or after surgery or radiotherapy. The cisplatin with or without prednisone regimen was used in 17 Group III patients for initial treatment or for relapse. The overall response rate among the patients receiving the cisplatin with or without prednisone regimen was 64%; 6 (35%) had a complete response, and 5 (29%) had a partial response. Thirty-one (36%) of the 87 total patients had 45 recurrent tumors; the lung (29%), pleura (22%), and mediastinum (18%) were the most common sites of recurrence, whereas bone was the most common distant metastatic site. The 5-year survival rate was 70% in patients with Stage I disease, 71% in patients with Stage II or III disease, and 46% in patients with Stage IV disease. The 10-year survival rate was 70% in patients with Stage I disease, 47% in patients with Stage II or III disease, and 21% in patients with Stage IV disease. Statistical analysis indicated a significant difference among the survival rates of patients with noninvasive Stage I, invasive Stage II plus III (P = 0.033), and Stage II plus III and IV tumors (P = 0.056), but not between patients with Stage II or III tumors. Patients with a major response to the cisplatin with or without prednisone regimen had a significant survival improvement compared to those with no response (P = 0.002, log-rank test).

CONCLUSIONS

Because thymoma is a chemosensitive tumor and frequently recurs in patients with Stage II or greater disease, chemotherapy carries a potential survival benefit and should be incorporated into the multimodality approach to prolong disease-free survival.

Tumor epidermal growth factor receptor studies in patients with non-small-cell lung cancer or head and neck cancer treated with monoclonal antibody RG 83852

PURPOSE

Tumor tyrosine kinase activity associated with the epidermal growth factor receptor (EGFR) and localization of anti-EGFR monoclonal antibody RG 83852 were studied in patients with non-small-cell lung cancer (NSCLC) and head and neck cancer.

PATIENTS AND METHODS

Fifteen patients were treated with escalating doses of RG 83852 by continuous intravenous infusion for 5 days. Fresh tumor specimens were obtained 24 hours after therapy in 10 patients (of whom five had a pretherapy sample taken). Tumor EGFR tyrosine kinase activity was determined in fresh tumor samples by autophosphorylation of EGFR isolated in immunocomplexes with RG 83852. Tumor EGFR saturation with RG 83852 was assessed semiquantitatively by comparing the EGFR tyrosine kinase activity in immunocomplexes of tumor specimens obtained after therapy with total EGFR tyrosine kinase activity assessed by exogenous addition of RG 83852 to tumor lysates. Modulation of EGFR tyrosine kinase activity after the administration of RG 83852 was assessed by comparing EGFR tyrosine kinase activity from the same malignant lesion obtained before and after therapy. Tumor localization of RG 83852 and EGFR saturation were also assessed by immunohistochemistry.

RESULTS

No significant side effects were observed up to a total dose of 600 mg/m2. Based on tyrosine kinase activity, a high degree of EGFR saturation (> or = 50%) was observed at doses > or = 200 mg/m2, and EGFR saturation was estimated to be 100% at a dose level of 600 mg/m2 both in tumor tissue and skin used as surrogate EGFR-positive tissue. Immunohistochemistry studies showed that RG 83852 localized in tumor tissue and skin, but not in stroma, at doses > or = 400 mg/m2, and high EGFR saturation was observed at 600 mg/m2. Tumor EGFR tyrosine kinase activity was studied in five patients (four with EGFR-positive tumors) before and 24 hours post-therapy; a threefold to fourfold upregulation of EGFR tyrosine kinase activity in posttherapy specimens was observed in two patients. Moderate upregulation of EGFR itself was suggested in both of these patients and in two additional patients by immunohistochemistry.

CONCLUSION

RG 83852 causes no toxic effects at doses that result in high tumor EGFR saturation. Treatment with RG 83852 may enhance EGFR tyrosine kinase activity and/or EGFR expression. Because high EGFR expression by tumors has been associated with increased sensitivity to cytotoxic therapy, the suggestion of antibody-mediated upregulation of EGFR by agents such as RG 83852 may prove useful in enhancing chemotherapeutic efficacy.

Methods in pathology. Optimization of proliferating cell nuclear antigen immunohistochemical staining by microwave heating in zinc sulfate solution

Immunohistochemical staining of routinely processed formalin-fixed, paraffin-embedded archival tissue sections with proliferating cell nuclear antigen (PCNA) monoclonal antibody has facilitated the understanding of the regulation of cell proliferation. However, false-negative staining due to masking or poor preservation of antigen epitopes by fixatives or other unknown conditions has been a major problem in PCNA immunohistochemical studies. Microwave heating (MWH) has been used to retrieve antigen in archival tissue. However, optimal staining conditions have not yet been defined. We therefore investigated the effect of MWH with or without a metal solution (zinc sulfate) on routinely processed paraffin-embedded tissue to determine the optimal conditions for retrieval of PCNA. The results were compared with routine immunohistochemical staining. We found that MWH in 1% zinc sulfate solution successfully retrieved PCNA; the optimal MWH time was 7.5 mins. In contrast, when MWH was performed in water, the specific intensity of PCNA expression was not increased because MWH not only enhanced the intensity of the antigen staining but also increased the background staining. In summary, MWH technique in zinc-sulfate solution allowed successful PCNA retrieval from formalin-fixed archival tissue and thus facilitated accurate immunohistochemical evaluation of cell proliferative activity in cancers.

Activation of p53 gene expression in premalignant lesions during head and neck tumorigenesis

With the goal of identifying a potential intermediate biomarker in the multistep process of head and neck cancer development, we conducted immunohistochemical analyses for p53 expression in 33 patients with head and neck squamous cell carcinomas whose tissue sections contained adjacent normal epithelium, hyperplastic, and/or dysplastic lesions. Fifteen of 33 (45%) squamous cell carcinomas of the head and neck expressed p53, but none of four normal control patients (cancer-free nonsmokers) expressed detectable p53 in oral mucosa specimens. To determine when p53 expression is initiated during head and neck tumorigenesis, we examined the normal and premalignant lesions adjacent to the tumors. Five of 24 (21%) samples of normal epithelium adjacent to tumors, 7 of 24 (29%) samples of hyperplasia, and 9 of 20 (45%) samples of dysplasia expressed p53. Quantitative image analysis demonstrated not only a gradual increase in the amount of p53 expression as tissue abnormalities progressed but also a topological change in expression. Whereas p53 expression, when present, was limited to the basal layer in normal epithelium adjacent to tumor, the expression of p53 expanded into the parabasal and superficial layers in hyperplasia and dysplasia. We conclude that p53 expression can be altered in very early phases of head and neck tumorigenesis. Thus, it may be an excellent candidate for risk assessment and may serve as an intermediate biomarker in chemoprevention trials.

Phase II clinical trial of didemnin B in previously treated small cell lung cancer

Didemnin B (NSC 325319), a cyclic depsipeptide isolated from a Carribean sea tunicate, exhibited potent antitumor activity in preclinical studies. After determining the maximum tolerated dose in our previous phase I/II trial, we conducted a phase II study of this drug in patients with previously treated small cell lung cancer; the starting dose was 6.3 mg/m2 intravenously over 30 min every 28 days. The major side effects were in the neuromuscular system and included severe muscle weakness, myopathy and/or myotonia by electromyography, and elevation of creatine phosphokinase and aldolase levels. We also observed modest increases in bilirubin and alkaline phosphatase levels. There were minimal hematologic toxic effects. No response was observed among 15 evaluable patients, leading us to conclude that didemnin B was toxic but inactive in patients with previously treated small cell lung cancer at the stated dose and schedule. A review of the literature revealed no significant antitumor activity in cancers of the colon, breast, ovaries, cervix, or lung (non-small cell) or in renal cell carcinoma. Further clinical trials for didemnin B may not be warranted at the stated dose and schedule.

Sequential increases in proliferating cell nuclear antigen expression in head and neck tumorigenesis: a potential biomarker

BACKGROUND

Proliferating cell nuclear antigen (PCNA) is a 36-kd nuclear protein whose expression is associated with DNA synthesis and cell proliferation. Tumorigenesis in head and neck squamous cell carcinoma is proposed to be a multistep process; dysregulation of proliferation is a potential marker of this process.

PURPOSE

PCNA dysregulation was analyzed in squamous cell carcinoma tissue samples containing premalignant lesions (hyperplasia and/or dysplasia) and in adjacent normal epithelium to better understand proliferative changes during head and neck tumor development.

METHODS

Immunohistochemical analysis was performed on formalin-fixed, paraffin-embedded sections by using a monoclonal anti-PCNA antibody. PCNA expression was analyzed in 33 head and neck squamous cell carcinomas and in their adjacent premalignant lesions from different sites and compared with that in the control samples, which had never been exposed to first-hand tobacco smoke. PCNA expression was assessed by semiquantitative scoring (scale 0-3) in three epithelial layers (basal, parabasal, and superficial). The labeling index and the weighted mean index of PCNA expression were calculated.

RESULTS

Normal epithelium adjacent to the tumor had much more proliferative activity than the controls: The weighted mean index of PCNA expression was four-fold higher in the basal layer and sixfold higher in the parabasal layer. PCNA expression increased as tissues progressed from adjacent normal epithelium to hyperplasia (P < .001), hyperplasia to dysplasia (P < .001), and dysplasia to squamous cell carcinoma (P = .065); the total increase in PCNA expression ranged from fourfold to 10-fold from adjacent normal epithelium to squamous cell carcinoma. PCNA expression was higher in the parabasal than in the basal layer at all premalignant stages (23 of 25 samples in adjacent normal epithelium, 12 of 13 in hyperplasia, and 17 of 22 in dysplasia). As the tissue progressed from normal through premalignant stages to squamous cell carcinomas, we observed not only incremental increases in the labeling index, but also incremental increases in PCNA expression per labeled cells.

CONCLUSIONS

These results indicate that PCNA could be a useful biomarker for multistep carcinogenesis in head and neck cancer and may serve as an intermediate end point in chemopreventive trials.

Increased polysomies of chromosomes 7 and 17 during head and neck multistage tumorigenesis

Head and neck cancer development has been proposed to represent a multistage process characterized by dysregulation of proliferation and differentiation and driven by an accumulation of genetic alterations in an anatomic field repeatedly exposed to carcinogens. To visualize the accumulation of genetic alterations during head and neck tumorigeneses and to determine the extent of the genetically altered field, we probed 25 squamous cell carcinomas of the head and neck and their adjacent premalignant lesions for numerical chromosome aberrations by nonisotopic, in situ hybridization using chromosome-specific centromeric DNA probes for chromosomes 7 and 17. Normal control oral epithelium from individuals free of cancer showed no chromosome polysomy (i.e., cells with > or = 3 chromosome copies), whereas histologically normal epithelium adjacent to the tumors showed squamous cells with polysomies for chromosomes 7 and 17. Moreover, the frequency of cells with polysomy increased as the tissues passed from histologically normal epithelium to hyperplasia to dysplasia to cancer. The finding of genotypic abnormalities in histologically normal and precancerous regions adjacent to the tumor supports the concept of field cancerization. The finding of progressive genetic changes as the tumor develops supports the concept of multistep carcinogenesis in the head and neck region. Such genotypic parameters could serve as biomarkers in the assessment of the risk of progression to malignancy and as intermediate end points in chemoprevention trials.

Phase II study of taxol in patients with untreated advanced non-small-cell lung cancer

BACKGROUND

Taxol, a complex plant product (a diterpene) extracted from the bark of Taxus brevifolia, has demonstrated substantial anticancer activity in ovarian and breast cancers, malignant melanoma, and acute myelogenous leukemia. Due to allergic reactions in phase I and early phase II studies, use of a 24-hour infusion of taxol with prophylactic dexamethasone, diphenhydramine, and cimetidine has been recommended.

PURPOSE

In this phase II study, we attempted to determine the efficacy and toxicity of taxol in patients with advanced (stage IIIB or IV) non-small-cell lung cancer who had never received chemotherapy.

METHODS

Patients were not excluded because of prior surgery or because of radiotherapy administered more than 4 weeks before study entry. Taxol was administered in the hospital at a dose of 200 mg/m2 as an intravenous infusion over 24 hours and repeated every 3 weeks, provided that patients had recovered from any toxic effects. Dexamethasone, cimetidine, and diphenhydramine were given before chemotherapy to prevent hypersensitivity reactions. Therapy was continued for at least two courses unless there was rapid disease progression and for at least three courses if no change was observed and no grade 3 or 4 toxic effects occurred. Treatment was continued for six more courses after maximum response or for two more courses after complete remission but was discontinued if disease progressed.

RESULTS

Of the 27 patients entered in the study, 25 were assessable for toxic effects and response. One patient had an allergic reaction that was not life threatening. The overall response rate was 24% (one complete response and five partial responses). An additional seven patients (28%) had minor response. Granulocytopenia was the dose-limiting toxic effect, and neutropenic fever occurred in eight of 118 courses. One additional patient developed neutropenic sepsis with hypotension but recovered with intensive treatment.

CONCLUSIONS

Taxol appears to have activity against non-small-cell carcinoma of the lung.

IMPLICATIONS

A phase II study combining taxol, etoposide, and cisplatin and using hematopoietic stimulating factors is now proposed. The optimal dose for combination chemotherapy has yet to be determined. An important consideration is potential cardiac effects of taxol with other drugs.

Activation of ribosomal protein S2 gene expression in a hamster model of chemically induced oral carcinogenesis

7,12-Dimethylbenz[a]anthracene (DMBA)-induced carcinogenesis of the hamster buccal pouch has been an excellent model for the study of squamous cell carcinogenesis in human head and neck cancer. Using a differential hybridization of cDNA cloning technique, we isolated a cDNA clone that is expressed in N-ras-transformed PA-1 cells but poorly expressed in non-tumorigenic PA-1 cells; the cDNA codes for the human ribosomal S2 gene product. To define the involvement of S2 gene expression during carcinogenesis in this animal model, we used in situ hybridization technique with non-radioactive digoxigenin-11-dUTP-labeled cDNA. S2 gene was expressed at low levels in basal and suprabasal cell layers of the epidermis in the control, but showed marked elevation throughout the epidermis other than the keratin layer in samples treated for 4 or 8 weeks; S2 was highly expressed in all malignant squamous cell carcinoma cells resulting from DMBA treatment for 16 weeks. As tumors progress from normal epithelium to squamous cell carcinomas, mRNA of the S2 gene was not only elevated sequentially, but also demonstrated the marked heterogeneity among transformed populations, particularly in dysplastic lesions and squamous cell carcinomas. The S2 gene was expressed in a stage-specific manner in the hamster tumor model; S2 could be useful as a neoplastic marker for the detection of certain epithelial origin of tumors and premalignant lesions as well.

Early genetic changes during upper aerodigestive tract tumorigenesis

Upper aerodigestive tract tumorigenesis has been hypothesized to represent a field cancerization process with multistep events based on its association with known carcinogens, its frequent associated premalignant lesions, and its multifocal clinical manifestation. To further explore this working hypothesis, we have examined normal tissue and premalignant lesions in the field of tumors for evidence of genetic change. Paraffin sections of head and neck tumors harboring neighboring premalignant lesions were explored for the presence of chromosome polysomies using in situ hybridization and chromosome-specific centromeric probes. Cells exhibiting random polysomy were observed in the premalignant regions near the tumors. The frequency of polysomy in the tumor field increased as the tissue progressed from normal morphology (33%), to hyperplasia (67%), to dysplasia (95%), and to squamous cell carcinoma (96%). These results support the notions of field cancerization and multistep tumorigenesis in the aerodigestive tract. To determine whether the degree of accumulated genetic alterations might serve as a biomarker for risk of developing malignancy, a set of biopsies of oral premalignant lesions (leukoplakia, erythroplakia) were retrospectively chosen for polysomy analysis from two groups of individuals: one group who subsequently developed oral cancer and one group who did not develop oral cancer. Three of the five individuals who showed significant chromosome polysomies in their biopsies subsequently developed oral cancer, whereas only one of eight individuals with little evidence of polysomy subsequently progressed to oral cancer. These results suggest that evidence of generalized genetic change or instability might be useful as a genetic biomarker for risk assessment.