Postoperative Follow-Up Strategy in Patients With Oral Squamous Cell Carcinoma

Improved recurrence rates and progression-free survival in primarily surgically treated oral squamous cell carcinoma - results from a German tertiary medical center

OBJECTIVES

This study aimed to explore survival and recurrence patterns in patients undergoing primarily surgical treatment for oral squamous cell carcinoma (OSCC) at a high-volume tertiary medical center in Germany.

MATERIALS AND METHODS

The study included 421 patients with primary OSCC who underwent radical tumor resection, neck dissection, and reconstruction with a free flap. Prognostic relevance of clinicopathological characteristics was assessed using Cox proportional-hazards models. Kaplan-Meier method estimated local recurrence-free survival, progression-free survival (PFS), and overall survival (OS), while the log-rank test compared survival outcomes between groups.

RESULTS

Recurrence manifested in 16.63% of the patients (70 patients), encompassing local recurrence in 54 patients (77.14%) and distant metastasis in 24 patients (34.28%). Neck recurrence occurred in only 1 patient (0.24%) on the contralateral side. The majority of recurrences occurred within the initial twelve months following primary tumor surgery (64.29%). Overall, the 5-year OS stood at 58.29%, while the 5-year PFS reached 72.53%. Patients with early recurrence within ≤ 12 months showed the least favorable prognosis (log-rank, all p < 0.001).

CONCLUSIONS

Our findings show a significant decrease in recurrence rates and enhanced PFS at a high-volume tertiary medical center in Germany compared to previous studies. Local recurrence was the primary form observed, with most recurrences happening within the initial twelve months post-surgery. Opting for treatment at a high-volume center and devising therapy plans in interdisciplinary tumor boards may not only enhance OS but also contribute to improved PFS.

CLINICAL RELEVANCE

These findings offer valuable insights for physicians regarding the post-treatment care of patients with OSCC. The results underscore the importance of frequent follow-up appointments, particularly during the initial year, and highlight the critical need for vigilance in monitoring for local recurrence.

Comparison of mutation landscapes of pretreatment versus recurrent squamous cell carcinoma of the oral cavity: The possible mechanism of resistance to standard treatment

BACKGROUND

A high recurrent rate of oral squamous cell carcinoma (OSCC) is a major concern in head and neck cancer treatment. The study of the genetic mutation landscape in recurrent OSCC may provide information on certain mutations associated with the pathobiology and treatment response of the OSCC.

AIM

We investigated the mutation landscape of matched pretreatment and recurrent tumors to understand the influence of genetic mutations on the pathobiology and clinical outcomes in OSCC.

METHODS AND RESULTS

We sequenced 33 formalin-fixed paraffin-embedded (FFPE) recurrent tumors, primary tumors, and primary tumors before recurrence that matched the recurrent tumors collected from Rajavithi Hospital during 2019-2021. We identified recurrent mutations from these samples by the Oncomine Ion Torrent-based next-generation sequencing on the 517 cancer-associated gene panel. From the results, we found that the most commonly mutated gene in the cohort is a histone methyltransferase KMT2D (54.55%), implicating that aberrance in epigenetic regulation may play a role in oral cancer tumorigenesis. Functional protein association network analysis of the gene frequently mutated in the recurrent tumors showed enrichment of genes that regulate the cancer cell cycle, that is, MRE11A, CDKN2A, and CYLD. This finding was confirmed in the primary-recurring matched pair. We found that recurrent tumors possess a small but recurring group of genes, with presumably the subclonal mutations driving the recurrence of the tumor, suggesting that the recurrent disease originated from a small fraction of the cancer cell that survives standard treatment. These genes were absent in the primary tumor with a good response to the standard treatment. On the other hand, we found an enrichment of DNA repair genes, namely ATR, BRCA1, BRCA2, RAD50, and MUTYH, in nonrecurrent tumors suggesting that the mutations in the DNA repair pathway may at least partially explain the different response to the standard treatment.

CONCLUSIONS

Our pilot study identified pathways of carcinogenesis in oral cancer and specific gene sets that indicate treatment responses and prognoses in this group of patients.

Risk of second primary cancer in patients with head and neck squamous cell carcinoma: a systemic review and meta-analysis

OBJECTIVES

Second primary cancer is a common event in patients with head and neck squamous cell carcinoma. However, the incidence and relevant factors vary by studies. We conducted a systematic review and meta-analysis of observational studies to estimate the incidence and relevant risk factors.

MATERIALS AND METHODS

PubMed and Web of Science were searched for studies published between January 2000 and December 2020 that reported the incidence of SPC in HNSCC patients. Per 1000-person-year incidence and odds ratios were used to estimate the incidence and potential risk factors. Due to the high heterogeneity, random-effects models were used to estimate the incidence and 95% confidence interval.

RESULTS

Seven thousand seven hundred thirteen articles were identified from the databases, in which 60 studies were included in this meta-analysis. The pooled incidence of the total, synchronous, and metachronous SPC in patients with HNSCC were 29.116 per 1000-person-year, 6.960 per 1000-person-year, and 26.025 per 1000-person-year, respectively. The head and neck region was the most common area where SPC occurred, followed by the lung (7.472 per 1000-person-year) and upper digestive tract (2.696 per 1000-person-year). Smoking, alcohol consumption, betel quid chewing, primary cancer of T1-2, and N0 were risk factors, while HPV infection (OR 0.47, 95% CI 0.30-0.72) was the protective factor.

CONCLUSIONS

SPC is frequently observed in HNSCC patients and had great impact on the prognosis. The findings could promote a more individualized follow-up strategy for SPC in HNSCC patients.

CLINICAL RELEVANCE

This systemic review and meta-analysis provide sufficient evidence for the establishment of the follow-up strategy for head and neck squamous cancer patients.

A nationwide study on cancer recurrences, second primary tumours, distant metastases and survival after treatment for primary head and neck cancer in the Netherlands

INTRODUCTION

There is no consensus on the optimal duration of post-treatment follow-up after head and neck cancer (HNC). To generate site-specific input for follow-up guidelines, this study describes the incidence and timing of manifestations of disease during five years of follow-up.

METHODS

All patients diagnosed with HNC in the Netherlands in 2015 were selected from the Netherlands Cancer Registry. The follow-up events local recurrence (LR), regional recurrence (RR), second primary tumour (SPT), distant metastasis (DM) and death were studied per follow-up-year. The cumulative incidence of these events was calculated using competing risk analyses, with LR, RR and SPT of the head and neck (SPHNC) as events and SPT outside the head-neck (SPOHN), DM and death as competing events. Analyses were performed for oral cavity-, oropharynx-, larynx- and hypopharynx squamous cell carcinoma (SCC), and all HNC patients.

RESULTS

The 1-, 1.5-, and 2-year cumulative incidence of an event (LR, RR, SPHNC) were 10% (95%CI 8-13), 12% (95%CI 10-15), and 13% (95%CI 10-16) for oral cavity SCC; 6% (95%CI 4-9), 10% (95%CI 7-14), and 11% (95%CI 8-15) for oropharynx SCC; 7% (95%CI 5-10), 11% (95%CI 9-15), and 13% (95%CI 10-16) for larynx SCC and 11% (95%CI 6-19), 19% (95%CI 12-27), and 19% (95%CI 12-27) for hypopharynx SCC.

CONCLUSIONS

One year of follow-up for oral cavity SCC, and 1.5 years for oropharynx-, larynx-, and hypopharynx SCC suffices for the goal of detecting disease manifestations after treatment. More research into other aspects of follow-up care should be performed to determine the optimal follow-up regimen.

The timing and methods for detection of recurrence in patients with head and neck cancer

BACKGROUND

Early detection of head and neck cancer recurrence after curative treatment is crucial for effective salvage treatment.

OBJECTIVE

We aimed to examine the timing and method that allowed early detection of recurrence in each primary and recurrence site.

MATERIALS AND METHODS

We enrolled 440 patients with head and neck squamous cell carcinoma (HNSCC) in the oral cavity, oropharynx, hypopharynx, or larynx who underwent curative treatment focusing on surgery at our hospital between 2009 and 2018. We examined the timing and diagnostic method (clinical examination, patient symptoms, or imaging examination) for HNSCC recurrence according to the primary and recurrence sites.

RESULTS

Recurrence was observed in 133 patients. In all primary sites, regional recurrence occurred significantly earlier than local and distant recurrences. Local recurrence occurred later in the larynx than in other primary sites. Furthermore, the clinical examination had a higher ratio of detection of local recurrence in the larynx than in the other primary site. Regardless of the primary site, more than half of the regional recurrences and most of the distant recurrences were detected by imaging examination.

CONCLUSIONS AND SIGNIFICANCE

Imaging examination is preferable for achieving early detection of regional and distant recurrences.

What is the Incidence of Oral Cancer Recurrence in Patients Reconstructed With a Microvascular Free Flap, Endosseous Implants, and an Oral Prosthesis and How Does the Timing of Implant Placement Influence Recurrence?

PURPOSE

In patients with malignant oral disease, there is concern that immediate implant placement at the time of ablative and microvascular free flap surgery can contribute to tumor recurrence or delay the diagnosis of recurrence. The purpose of this study is to 1) estimate the incidence of recurrence in patients with malignant disease treated with immediate microvascular free flap reconstruction, endosseous implants, and an oral prosthesis, 2) measure and compare the timing of implant placement, immediate versus delayed, and the time to complete oral rehabilitation, and 3) measure the association between the timing of implant placement and tumor recurrence.

MATERIALS AND METHODS

This is a retrospective cohort study utilizing medical record analysis involving patients with malignant oral cancer undergoing tumor resection and immediate microvascular reconstruction from 1996 to 2019 at the Mayo Clinic, Rochester, MN by the Division of Oral and Maxillofacial Surgery. Additional inclusion criteria comprised of immediate or delayed endosseous implant placement, the fabrication of an oral prosthesis, and a minimum of 2-year follow-up. Data on patient demographics, tumor characteristics, timing of implant placement and prosthesis loading, type of prosthesis, tumor recurrence, or second primary tumor events were analyzed.

RESULTS

Thirty-three patients with a mean follow-up of 6.4 years were included. Twenty-four patients (72.7%) were diagnosed with squamous cell carcinoma with 3 patients experiencing tumor recurrence. Fifteen patients had immediate implant placement while 18 patients had delayed implant placement. The mean number of days to prosthetic loading of the implants was 680.4 days and 330.1 days for the delayed implant group and immediate implant group, respectively, which was statistically significant (P = .004). The timing of implant placement and the event of a recurrence were not statistically significant (P = .075).

CONCLUSION

The incidence of recurrence in patients with malignant oral cancer treated with microvascular reconstruction, endosseous implants, and an oral prosthesis was 12.5% with one recurrence occurring beneath the oral prosthesis. Delayed implant placement resulted in a statistically significant delay in the completion of oral rehabilitation compared to immediate implant placement. There was no difference in the incidence of recurrence in the immediate implant group compared to the delayed implant group.

Tumor Recurrence and Follow-Up Intervals in Oral Squamous Cell Carcinoma

Tumor recurrence in oral squamous cell carcinoma (OSCC) is frequent. However, no consensus about follow-up interval is available. The aim of this study was to analyze the recurrence pattern, detection method and associated parameters for possible risk stratification. Histopathological and epidemiological features were obtained retrospectively and correlated with tumor recurrence and overall survival, distant and lymph node metastases. A total of 760 patients were included, of which 216 patients showed tumor recurrence (mean after 24 ± 26 months). Within the first 12 months, 24% of the recurrences were detected. The primary detection method was clinical examination (n = 123, 57%). Tumor recurrence significantly correlated with advanced histopathological grading (G2/3 vs. G1, p < 0.000) and lymph node metastasis (p = 0.004). Tumor recurrence was frequent. Clinical examination was the primary detection method and manifestation within the first 6−12 months was high. The degree of histopathological grading may be useful for risk stratification.

TNM 8 staging is a better prognosticator than TNM 7 for patients with locally advanced oral cavity squamous cell carcinoma treated with surgery and post-operative radiotherapy

PURPOSE

To assess TNM 8 staging in discriminating overall survival (OS) amongst patients with locally advanced oral cavity squamous cell carcinoma (OCSCC) treated with surgery and post-operative radiotherapy (PORT), compared to TNM 7.

MATERIAL AND METHODS

Data from OCSCC patients treated with surgery and PORT between January 2010 and December 2018 were reviewed. Demographics, tumour characteristics and treatment response data were collected, and patients staged according to both TNM 7 and TNM 8. OS and disease free survival (DFS) were estimated using the Kaplan Meier method. Univariate and multivariable analyses were conducted for factors affecting OS, DFS and early disease recurrence within 12 months.

RESULTS

Overall 172 patients were analyzed. Median follow up was 32 months for all patients and 48 months for surviving patients. TNM 8 staging demonstrated significant stratification of OS and DFS amongst the entire cohort, whereas TNM 7 staging did not. On multivariable analysis, TNM 8 stage, performance status (PS) and a positive surgical margin were prognostic for OS. Looking at disease recurrence within 12 months, TNM 8 stage IVB, presence of lymphovascular invasion (LVSI), younger age and lesser smoking history were predictive factors on multivariable analysis.

CONCLUSION

TNM 8 is a good development of its predecessor in terms of predicting survival for patients with locally advanced OCSCC. We have also identified younger age (<60 years) and a smoking history of <10 pack years as risk factors for early disease recurrence, potentially representing a separate biological cohort within OCSCC patients.

Time patterns of recurrence and second primary tumors in a large cohort of patients treated for oral cavity cancer

INTRODUCTION

Routine follow-up after curative treatment of patients with oral squamous cell carcinoma (OSCC) is common practice considering the high risk of second primaries and recurrences (ie second events). Current guidelines advocate a follow-up period of at least 5 years. The recommendations are not evidence-based and benefits are unclear. This is even more so for follow-up after a second event. To facilitate the development of an evidence- and personalized follow-up program for OSCC, we investigated the course of time until the second and subsequent events and studied the risk factors related to these events.

MATERIALS AND METHODS

We retrospectively studied 594 OSCC patients treated with curative intent at the Head and Neck Cancer Unit of the Radboud University Medical Centre from 2000 to 2012. Risk of recurrence was calculated addressing death from intercurrent diseases as competing event.

RESULTS

The 1-, 5- and 10-year cumulative risks of a second event were 17% (95% CI:14%;20%), 30% (95% CI:26%;33%), and 37% (95% CI:32%;41%). Almost all locoregional recurrences occurred in the first 2 years after treatment. The incidence of second primary tumors was relatively stable over the years. The time pattern of presentation of third events was similar.

DISCUSSION

Our findings support a follow-up time of 2 years after curative treatment for OSCC. Based on the risk of recurrence there is no indication for a different follow-up protocol after first and second events. After 2 years, follow-up should be tailored to the individual needs of patients for supportive care, and monitoring of late side-effects of treatment.

Detection of high PD-L1 expression in oral cancers by a novel monoclonal antibody L1Mab-4

Programmed cell death-ligand 1 (PD-L1), which is a ligand of programmed cell death-1 (PD-1), is a type I transmembrane glycoprotein that is expressed on antigen-presenting cells and several tumor cells, including melanoma and lung cancer cells. There is a strong correlation between human PD-L1 (hPD-L1) expression on tumor cells and negative prognosis in cancer patients. In this study, we produced a novel anti-hPD-L1 monoclonal antibody (mAb), L₁Mab-4 (IgG_2b, kappa), using cell-based immunization and screening (CBIS) method and investigated hPD-L1 expression in oral cancers. L₁Mab-4 reacted with oral cancer cell lines (Ca9-22, HO-1-u-1, SAS, HSC-2, HSC-3, and HSC-4) in flow cytometry and stained oral cancers in a membrane-staining pattern. L₁Mab-4 stained 106/150 (70.7%) of oral squamous cell carcinomas, indicating the very high sensitivity of L₁Mab-4. These results indicate that L₁Mab-4 could be useful for investigating the function of hPD-L1 in oral cancers.

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Programmed cell death-ligand 1 (PD-L1) is expressed in many cancers.

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PD-L1 expression has not been fully investigated in oral cancers.

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A novel anti-PD-L1 mAb L₁Mab-4 was developed in this study.

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L₁Mab-4 stained 70.7% of oral SCCs in a membrane-staining pattern.

Cytokeratin 17 mRNA as a prognostic marker of oral squamous cell carcinoma

Despite diagnostic and therapeutic advances, the 5-year survival rate of oral squamous cell carcinoma (OSCC) remains between 70–80% due to recurrences and secondary metastases to cervical lymph nodes. It is difficult to find these recurrences and metastases postoperatively, thus, careful follow-up is recommended. Cytokeratins (CKs) are intermediate filaments of the cytoskeleton and candidate prognostic biomarkers for OSCC, as they are overexpressed in OSCC compared with normal mucosa. The aim of the present study was to determine the relative levels of occurrence of 3 CK mRNA (CK17, CK19, CK20) transcripts in peripheral blood mononuclear cells (PBMC) using reverse transcription-quantitative polymerase chain reaction. The study comprised pre- and post-operative PBMC samples from 19 OSCC patients. In the good-prognosis group, 10 of 13 patients demonstrated reduced CK17 mRNA expression post-operatively, compared with pre-operative samples, conversely, only 3 of 6 patients in the poor-prognosis group had reduced post-operative CK17 mRNA expression. This difference was statistically significant (P<0.01). The disease-free survival rate of the group with reduced post-operative CK17 mRNA expression was significantly increased compared with the elevated CK17 mRNA group (P<0.01); however, the overall survival rates of the two groups were not significantly different. Neither CK19 mRNA nor CK20 mRNA were significantly expressed in the PBMC of OSCC patients. Overall, CK17 mRNA expression may be a useful prognostic biomarker for OSCC.

Follow-up of oral cancer patients: three uneventful years may be enough

OBJECTIVE

To explore the possibility of shortening the length of follow-up from 5 to 3 years in patients who have undergone curative treatment of an oral squamous cell carcinoma.

STUDY DESIGN

The medical records of 225 patients who had undergone initial curative treatment at the VU University Medical Center in Amsterdam, the Netherlands, between 2004 and 2009 were analyzed.

RESULTS

In 96 patients (42.7%) a secondary event occurred. Eighty-six percent of the secondary events were detected within 3 years. In the fourth and fifth years, 14% of the secondary events were found, consisting mainly of second primary tumors.

CONCLUSIONS

Most secondary events occurred within the first 3 years of follow-up. Therefore, the case can be made for an altered regimen of follow-up beyond 3 years based on certain risk factors unique to the patient as well as the patient's ability to adequately report symptoms that may be associated with recurrent disease.

A new surgical strategy for treatment of tongue squamous cell carcinoma based on anatomic study with preliminary clinical evaluation

BACKGROUND

This study characterized the infiltration of primary tumors along the intrinsic and extrinsic muscles of the tongue in oral tongue squamous cell carcinoma (OTSCC), to create a new surgical strategy that is suitable for most stages. A preliminary evaluation of this novel surgical approach was also conducted.

METHODS

An anatomic study of macroscopic specimens from 10 human cadavers and 100 OTSCC patients was conducted. The anatomic characteristics of the primary tumors and the origin and distribution of fibers of the intrinsic and extrinsic tongue muscles were observed and measured. After initial treatment with curative intent, the 100 patients were regularly followed-up with clinical examination and imaging.

RESULT

Based on the anatomic characteristics of the primary tumors and tongue muscles, a new surgical approach was developed, and was described as muscle anatomy tongue surgery (MATS). MATS proved suitable for almost all stages of OTSCC. According to the morphology of the invasive tumor front, the 100 cases were divided into four types. The rate of 2-year local disease control was 98%, locoregional control 86%, disease-free survival 85%, and overall survival 89%. Tongue functions were perfectly recovered in more than 60% of the patients.

CONCLUSION

Application of the principles of MATS to the treatment of OTSCC proved suitable for almost all stages of the disease. MATS is a novel surgical technique that may improve outcomes in tongue cancer surgery.

Loco-regional recurrence after surgical treatment of oral squamous cell carcinoma: Proposals for follow-up imaging based on literature, national guidelines and institutional experience

The recurrence rate following the treatment of oral squamous cell carcinoma (OSCC) by primary surgery is about 10%-26%. The earliest possible diagnosis of residual tumour, recurrence of local tumour disease, and subsequent metastasis is essential for an improvement of the overall survival and of the survival period for affected patients. No international consensus exists for a post-therapeutic surveillance schedule for OSCCs. Based on a review of the literature, existing guidelines, and our institutional experience, we have established an algorithm for the follow-up of these patients regarding the timing and techniques of postoperative imaging. We recommend a follow-up interval of 6 weeks during the first half-year after discharge from hospital by single clinical and alternating clinical check-ups combined with computed tomography (CT) or magnetic resonance imaging (MRI), followed by an interval of 3 months in the second half-year, with clinical and radiological check-ups. In year 2, we recommend a follow-up interval of 3 months with single clinical and alternating clinical check-ups combined with CT or MRI. In year 3, we recommend screening every 6 months, both clinically and via imaging, because of the decreased risk of recurrence. From year 5 onwards, our recommendation is a clinical and imaging-based examination every 6-12 months, depending on patient risk factors and disease progression. Four standard imaging techniques, namely positron emission tomography (PET), CT, MRI, and ultrasound (US), are discussed concerning their range of application, sensitivity, and specificity. Furthermore, the technical aspects of our institutional protocols are described in detail. In highly frequented head and neck cancer centres, PET and US are of secondary importance, since CT and MRI are nowadays highly efficient tools in primary diagnostic and post-therapeutic surveillance.

Outpatient follow-up appointments for patients having curative treatment for cancer of the head and neck: are the current arrangements in need of change?

Although there are recommendations, there is little evidence about the rationale for the frequency and duration of review appointments for patients with cancer of the head and neck. We have recorded the pattern of follow-up in a tertiary cancer centre and its association with survival and recurrent disease. We used clinical letters and a prospectively maintained database to obtain details on 297 patients who were treated curatively for squamous cell carcinoma (SCC) of the oral cavity between 2005 and 2008. Mean (SD) age was 63 (12) years and 58% (n = 171) were male. Most patients were seen about 6 times in year one, 3 times in year 2, twice in year 3, twice in year 4, once or twice in year 5, and once yearly beyond year 5. Fewer clinics were scheduled for and attended by patients over 75 years of age, those with overall clinical grades 0-1, and those treated by operation alone in contrast to those who also had adjuvant radiotherapy. Patients were usually seen about 15 times over the 5 years. Taking into account the stage of the tumour and overall mortality, the number and timing of follow-up visits is adequate for the needs of patients with stage II-IV disease. Those with stage I disease may be considered for discharge after the third year if they are told about the risk factors, and signs and symptoms of recurrent disease, and surveillance in primary care.

Post-therapeutic surveillance schedule for oral cancer: is there agreement?

INTRODUCTION

Patients with oral cavity squamous cell carcinoma represent a diverse group, and the treatment these patients undergo also varies widely. Some patients undergo local excision alone while others require extensive surgery, often with adjuvant chemoradiotherapy. The post-therapeutic surveillance schedule for these patients tends to be a "one size fits all" formula for all head and neck squamous cell carcinoma patients, which has often been dictated by institutional doctrine or a senior surgeon's dogma. The post-therapeutic needs and risks of a T1 oral cancer patient treated with surgery alone differ from those of a patient with advanced laryngeal carcinoma, and the follow-up regimen should be tailored to the specific patient's risk of loco-regional recurrence, distant metastasis, and other related medical issues.

RESOURCES AND MATERIALS

A total of 65 papers were identified, 18 of which either focused on follow-up strategy for oral cavity squamous cell carcinoma or their tabular data allowed these cases to be extracted. Internationally recognized cancer entities were also queried.

CONCLUSIONS

No international consensus was achieved about the follow-up strategies. The value of post-therapeutic surveillance schedule following oral cancer treatment is generally not in dispute, although patient-initiated symptom-driven visits can be effective in identifying tumor recurrence for oral cancer patients. The range of appointment interval schemes tends to identify a progressive escalation of visit intervals such that there are more visits in the first year than in the second, and fewer yet during the third. Patients may fail to comply with their clinic visit structure. Most references agree that follow-up beyond the third year is unnecessary and may waste medical resources as well as the time of both patient and surgeon. There is no agreement as to the need for or interval of imaging studies.

Association of cytokeratin 17 expression with differentiation in oral squamous cell carcinoma

PURPOSE

The aim of this study was to confirm the expression profile of cytokeratin (CK)17 in comparison with that of CK13 in oral squamous cell carcinoma (OSCC) and leukoplakia and to clarify an association of CK17 with the OSCC differentiation.

MATERIALS

The expression of CK17 and CK13 was immunohistochemically examined in 105 patients with OSCC and 108 patients with leukoplakia. A correlation of CK expression with clinicopathological variables was carried out. The over-expression levels of CK17 mRNA were analyzed by real-time RT-PCR in 5 OSCC cell lines (HSC-2, HSC-3, SAS, SQUU-A, SQUU-B).

RESULTS

CK17 and CK13 were detected in 101 (96.2 %) and three (2.9 %) of the 105 OSCCs, respectively. CK17 was significantly expressed in well-differentiated OSCC compared to moderately/poorly differentiated OSCC (p < 0.01). As detected in 19 of the 34 dysplastic leukoplakias (55.9 %) and 36 of the 74 hyperplastic leukoplakias (48.6 %), CK17 was significantly expressed in dysplastic leukoplakias (p < 0.01). As detected in 11 of the 34 dysplastic (32.4 %) and 52 of the 74 hyperplastic leukoplakias (70.3 %), CK13 was significantly expressed in hyperplastic leukoplakias (p < 0.01). The relative expression of CK17 mRNA in HSC-2 was significantly higher than in HSC-3 and SAS (p < 0.05). Moreover, the relative expression of CK17 mRNA in SQUU-A was significantly higher than in SQUU-B (p < 0.05).

CONCLUSION

CK17 expression could be associated with the differentiation and the malignancy of OSCC. A combination pattern of CK17/CK13 might be a suitable marker of malignant transformation.