Outcomes of Patients with Oral Cavity Squamous Cell Carcinomas Treated with Adjuvant IMRT with Perineural Invasion

PURPOSE/OBJECTIVE(S)

Patients with advanced oral cavity squamous cell carcinoma (OCSCC) have high rates of recurrence and dismal outcomes. Treatment consists of definitive surgery followed by risk-adapted adjuvant radiation therapy based on pathologic review. Perineural invasion (PNI) is thought to be an intermediate risk factor, leading to clinical uncertainty as to adjuvant therapy in the setting of PNI. We performed a single institution retrospective review of patients with OCSCC treated with adjuvant radiation with or without PNI and examined relapse-free survival (RFS) and overall survival (OS).

MATERIALS/METHODS

We performed a single-institutional retrospective review of patients with OCSCC treated with adjuvant IMRT +/- chemotherapy after surgical resection from July 2002- August 2021 using our institution's Head and Neck SPORE database. Time to recurrence or death was calculated from end of RT. OCSCC within 5 years of RT was considered a recurrence, beyond this timeframe any OCSCC was considered a new primary. Univariate analysis of predictors for RFS and OS were performed using the Kaplan-Meier method with log-rank test. Factors significant on univariable analysis were entered into parsimonious cox multivariable analysis using forward selection methodology. A p-value <0.05 was considered significant in both analyses.

RESULTS

In total, 494 patients with OCSCC were identified that received surgery and adjuvant IMRT. In this cohort, 48.8% of patients had pT4 tumors, 62.2% of patients had nodal involvement, and 40.3% of patients had extranodal extension. PNI was present in 63.6% of patients (n = 314). With regards to tumor subsite, 40.9% originated from the oral tongue, 21.5% originated from the gums, 18% originated from the floor of mouth, and 19.6% from the other sites. Median age was 59 years, and median adjuvant RT dose was 63 Gy (Interquartile range [IQR]) 60-66 Gy). The majority of patient received platinum-based chemotherapy (51.8%), and 44.1% of patients did not receive adjuvant chemotherapy. The 3-year RFS and OS with a median follow-up of 32 months (IQR 12-69 months) is presented in Table 1. On univariable analysis for OS, T stage (p = 0.003), N stage (p<0.001), PNI (p = 0.005), extranodal extension (ENE) (p<0.001), margin status (p = 0.038), and chemotherapy (p<0.001) were significant. On multivariable analysis, T stage (p<0.001), N stage (p = 0.010), PNI (p = 0.017), and ENE (p = 0.007) remained significant. Similar results were seen in the RFS analysis.

CONCLUSION

In this large single institution study, PNI was a significant and independent negative predictive factor for RFS and OS in patients with OCSCC that had received definitive surgery followed by adjuvant IMRT. To our knowledge this is the largest study of its kind, and these findings can help guide clinical decision making for these patients.

RAS mutations in thyroid FNA specimens are highly predictive of predominantly low-risk follicular-pattern cancers

INTRODUCTION

RAS mutations are common in thyroid tumors and confer a high risk of cancer when detected in fine-needle aspiration (FNA) specimens. Specific characteristics of RAS-positive thyroid cancers are not well described.

METHODS

From April 2007 to April 2009, 921 consecutive patients undergoing FNA were evaluated prospectively with a panel of molecular markers. Ultrasonographic, cytological, histological, and surgical outcomes were retrospectively assessed.

RESULTS

Sixty-eight aspirates from 66 patients were positive for RAS mutations including 63 cytologically indeterminate (93%), 3 malignant (4%), and 2 benign (3%) specimens. Cancer was histologically confirmed in 52 of 63 aspirates (83%) including the following: 46 papillary thyroid cancers, 4 follicular thyroid cancers, 1 medullary cancer, and 1 anaplastic cancer. All 46 RAS-positive papillary thyroid cancers, including 1 metastatic cancer, had follicular variant histology papillary thyroid cancer; only 11 tumors demonstrated vascular/capsular invasion and 4 had infiltrative growth. Of 48 patients with differentiated thyroid cancer, lymph node metastasis was uncommon and bilateral cancer was present in 48%. Only 33% of malignant nodules were suspicious by preoperative ultrasonography. At a mean follow-up of 22 months, 31 of 35 differentiated thyroid cancer patients (89%) have no evidence of recurrence, 4 patients (9%) have detectable thyroglobulin, 1 patient has bone metastases, and both patients with medullary and anaplastic cancer have died.

CONCLUSION

Most RAS-positive thyroid cancers have indeterminate cytology, lack suspicious ultrasound features, and are histologically low-grade follicular variant histology papillary thyroid cancer. Lymph node and distant metastases are uncommon but bilateral disease is frequent. Total thyroidectomy should be considered for initial surgical management of most patients with RAS-positive FNA results. The role of prophylactic lymphadenectomy remains unclear.

Fluorescence polarization competition immunoassay for tyrosine kinases

To increase the sensitivity and throughput of protein tyrosine kinase (PTK), simple, homogeneous, nonradioactive, direct and indirect fluorescence polarization (FP) protein tyrosine kinase immunoassays have been developed that are compatible with high-throughput and ultrahigh-throughput screening for developing drugs. In the direct method, a fluorescinylated peptide substrate is incubated with the kinase, ATP, and antiphosphotyrosine antibody. The phosphorylated peptide product is immunocomplexed with the antiphosphotyrosine antibody, resulting in an increase in the polarization signal. Since the direct method can be used only with a peptide substrate and requires large amounts of antiphosphotyrosine antibody, a modified indirect method, wherein a phosphorylated peptide or protein produced by kinase reaction will compete with a fluorescent phosphopeptide used as a tracer for immunocomplex formation with phosphotyrosine antibody, was developed. In this format kinase activity will result in loss of the polarization signal. Both the direct and indirect FP-PTK immunoassays have been compared with a more commonly used (32)PO(4) transfer assay and validated using lymphoid T-cell protein tyrosine kinase (Lck). In both assays, Lck activity showed a similar dependence on ATP, Lck enzyme, and peptide substrate concentration, comparable to the (32)PO(4) transfer assay. Inhibition by staurosporine and the Lck inhibitor 4-amino-5-(methylphenyl)-7-(tert-butyl)pyrazolo[3, 4-d]pyrimidine in these two FP assays was similar to that obtained in the (32)PO(4) transfer assay. The advantages of these FP-PTK assays over the other kinase assays, besides high sensitivity, are use of inexpensive nonisotropic substrate; environmental safety; homogeneous nature of FP kinase assays that are done in the same tube (or in a well of 96- or 384-well microtiter plates), without separation, precipitation, or washing; and increase of throughput.

A fluorescence polarization competition immunoassay for tyrosine kinases

We have recently reported a homogeneous, nonradioactive fluorescence polarization method to assay protein tyrosine kinase activity. Our original approach can only be used with a peptide substrate and requires large amounts of anti-phosphotyrosine antibody. To overcome these problems an alternate fluorescence polarization competition immunoassay was designed and evaluated. In this assay, phosphorylated peptide or protein produced by kinase reaction will compete with a fluorescent phosphopeptide used as a tracer for immunocomplex formation with phosphotyrosine antibody. In this format kinase activity will result in the loss of the polarization signal. To validate the fluorescence polarization competition immunoassay, Lck activity was compared with a more commonly used 32PO4-transfer assay using Lck peptide or enolase as the substrate. In both the assays, Lck activity showed a similar dependence on ATP, Lck enzyme, and the peptide/enolase substrate concentrations with the FP signal inversely proportional to the amount of 32PO4 transferred to the substrate. Inhibition by staurosporine and the Lck inhibitor 4-amino-5-(methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine was similar in these two assays. The advantages of this assay over other kinase assays include use of nonisotopic substrates and a more simple procedure in which the kinase assay is done in a single tube (well of a microtiter plate), without separation, precipitation, or washing. This method is easily automated for high-throughput drug discovery screening.

A homogeneous, fluorescence polarization assay for src-family tyrosine kinases

A nonradioactive, simple, sensitive fluorescence polarization assay was developed to assay protein tyrosine kinase activity. This assay involves incubation of a fluorescenylated peptide substrate with the kinase, ATP, and anti-phosphotyrosine antibody. The phosphorylated peptide product is immunocomplexed with the anti-phosphotyrosine antibody resulting in an increase in the polarization signal as measured in a fluorescence polarization analyzer. Among several anti-phosphotyrosine antibodies examined, monoclonal antibody PY54 was found to give the best polarization signal with the test peptide. For validation of the fluorescence polarization assay, Lck activity was compared with a 32PO4 transfer assay. In both the fluorescence polarization and 32PO4 transfer assays, Lck activity showed a similar dependence on ATP, Lck enzyme, and peptide substrate concentrations. Both assays gave similar inhibition constants with a known tyrosine kinase inhibitor staurosporine and the Lck inhibitor, 4-amino-5-(methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine. These results show that the fluorescence polarization assay can detect inhibitors and is comparable to the 32PO4 transfer assay. The fluorescence polarization method is advantageous compared to the 32PO4 transfer assay or ELISA or DELFIA because it is a one-step assay that does not involve several washings, liquid transfer, and sample preparation steps. It has the added advantage of using nonisotopic substrates. The fluorescence polarization assay thus is environmentally safe and minimizes handling problems. The homogeneous nature of the assay makes it readily adaptable to high-throughput screening for small-molecule drug discovery.

BMS-192548, a tetracyclic binding inhibitor of neuropeptide Y receptors, from Aspergillus niger WB2346. I. Taxonomy, fermentation, isolation and biological activity

During the screening of microbial fermentation extracts for their ability to inhibit the binding of 125I-peptid YY (PYY) to the neuropeptide Y (NPY) receptor using the scintillation proximity assay (SPA), BMS-192548 was isolated from the extract of Aspergillus niger WB2346 by bioassay-guided fractionation. BMS-192548 showed the inhibitory activity against 125I-PYY binding to SK-N-MC and SMS-KAN cells, which express NPY1 and NPY2 receptors, respectively, with IC50 values of 24 microM in Y1 and 27 microM in Y2 receptor binding. BMS-192548 demonstrated weak cytotoxicity against murine tumor cell line M-109 with an IC50 value of 240 microM.

Cloning and functional expression of a cDNA encoding a human type 2 neuropeptide Y receptor

Neuropeptide Y (NPY) is a 36-amino acid polypeptide that is widely distributed in the central nervous system and periphery. Pharmacological studies have suggested that there are at least three receptor subtypes, Y1, Y2, and Y3. Cloning of the Y1 subtype has been reported previously. Here we report the isolation by expression cloning of a cDNA encoding a human NPY receptor displaying a pharmacology typical of a Y2 receptor. COS-7 cells transfected with the cDNA express high affinity binding sites for NPY, peptide YY, and NPY13-36, whereas [Leu31,Pro34]NPY binds with lower affinity. The receptor is 381 amino acids in length and has seven putative transmembrane regions typical of G-protein-coupled receptors. Comparison of the amino acid sequence of this Y2 receptor to that of the human Y1 receptor indicates that the two receptors are 31% identical at the amino acid level. Northern blot analyses reveal a single 4-kilobase mRNA species and indicate that the messenger RNA is present in many areas of the central nervous system. NPY induced calcium mobilization and inhibited forskolin-stimulated cAMP accumulation in Chinese hamster ovary cells that stably express the Y2 receptor cDNA, indicating that the recombinant Y2 receptor is functionally coupled to second messenger systems.