| Oral squamous cell carcinoma is the most common malignant tumor in oral gnathofacial region, which accounts for over 80 percent. It recur and transfer easily with only a survival rate of 45 to 50 percent in 5 years, so until now, there has not been a single treatment and the improvements of cure rate and survival rate depend on complex treatment. Most scholars have a consensus that oral squamous cell carcinoma should be treated with complex treatment by applying the present means. The basic model of treating tumor is preoperative adjuvant chemotherapy + operation + postoperative chemotherapy or radiotherapy and biotherapy. In recent ten years, preoperative adjuvant chemotherapy has been one of the common treatments in cephalocervical malignant tumor. As one of the important means for treating malignant tumor, preoperative adjuvant chemotherapy improves the cure rate and the survival rate of malignant tumor patients, as well as improves the life quality of the patients, as a unique advantage, that has gained the encouraging result. The blood supply of the tumor undisturbed by operation is fine and beneficial for the absorption and the distribution of chemotherapeutic medicine, whose effect of killing tumor could be fully developed. And preoperative adjuvant chemotherapy can shrink the size of tumor vastly, reduce the small transference of focus in operation and after operation, improve the quality of radical operation, and create the operative chance for those unable to have operation. The short-term curative effect of preoperative adjuvant chemotherapy in treating oral squamous cell carcinoma has been approved fully. Whereas after tumor shrunk in effective patients for preoperative iadjunant chemotherapy, what range should be followed for excising primary focus, has not have a clear standard until now. Most scholars advocate that the excisable innerboundary should be defined as 1-2 cm out of clinical boundary before induction adjuvnant chemotherapy, to ensure a thorough operation, but without basic experimental evidence. Due to the anatomical and functional characteristics of carcinoma located in oral and maxillofacial region, unnecessary over wide excision will harm the appearance and damage the important functions of the patient, such as speaking, eating, swallowing etc, thus influence the life quality of the patients.At present, the safety margin of shrunk tumor after induction adjuvnant chemotherapy has not defined, and rarely reported in systematic study, especially not reported in clinical study, and the measurement of safety boundary after induction adjuvnant chemotherapy in molecular level has not reported yet. By clinical examination, biotechnic and immunohistochemical technic, and electron microscopy and optical microscopy of clinical cases, the paper intend to systematically study the cell morphologic variation in the tumor shrunk region, the definition of pathological and molecular boundary, and relevant alterative regularity of microenvironment after preoperative induced chemotherapy for oral cancer, to provide evidence for defining clinical safety boundary after chemotherapy and designing margin in a scientific and rational way.The study is divided into three parts:I. Pathological boundary studyWe adopted routine pathological slice and penetrating electron microscopy to have pathological observation on 10 cases of tissues in the shrunk region of tumor effective for preoperative adjuvnan chemotherapy. We found that in the shrunk region, there were small amount of tumor cells remained, and scattered distributed, and degenerated, in which infiltrated by some lymphocytes and megoxycytes. The remained tumor cells in the shrunk region, was 9.0 mm of farthest level distance from clinical boundary after tumor shrunk by chemotherapy, the basic farthest boundary was only 6.0 mm, that suggest for patients of oral squamous cell carcinoma who are effective for chemotherapy, the operative safety excisable boundary can be defined as 1.5 cm out of clinical boundary after tumor shrunk.II. Molecular boundary studyWe adopted immunohistochemical technic, hybridization technic in situ, and flow cytometrc analysis to examine the expression, cell cycle, and DNA content of P53, Bcl-2, Bax, hTERT, Ki-67, and VEGF, which now closely related with oral squamous cell carcinoma and chemotherapy. We found tissues in tumor shrunk region, negative in pathological examination, expressed positive in molecular labeled compound variously, in which positive rate of expressing P53 was 8.30 + 3.25%; hTERT, 10.25 + 3.82%; Bcl-2, 17.59 + 5.32%; Ki-67, 11.28 ±3.77%; and VEGF, 11.38 + 3.13%, that suggest we can not completely exclude remains of small focus only depending on negative in pathological examination. FCM analyzed DNA content, and found that Prolix-ferative index was 0.07 + 0.02 and cell rate in S phase was 1.65 ±1.14, whereas apoptosis index was 12.39 ±5.41 and positive rate of expressing Bax was 49.78 ± 9.35. Analyzing and comparing tumor body after chemotherapy and tissues in tumor shrunk region, we found that proliferative activity of tumor cells remained in tumor shrunk region was remarkably declined whereas death index was remarkably increased, that suggest activity of remained tumor cells is declined. Moreover, we found hTERT was the most sensitive by measurement, and the farthest level distance of positive cells was 10 mm, and the farthest vertical distance was 8.5 mm, so we suggest the operative excisable range should be 1.5 cm out of clinical boundary of tumor shrunk region, but not the range of original tumor before chemotherapy, so to be safe and preserve tissues and organs.III. Action of chemotherapeutic medicine inducint the apototsis of Tca8113 We took human tongue cancer cell series, Tca8113, as research object, adopted optical microscopy, electron microscopy, immunohistochemical technic, hybridication technic in situ, and flow cytometrc analysis to observe morphological characteristics of apototsis Tca8113 induced by single chemotherapeutic medicine cis-diammine,l-cyclobutane dicarboxylate platinum amethopterin,metbotrexate, pingyangmycycin, or united the above three respectively, and examine the influence of chemotherapeutic medicine for expressing relevant death gene protein Ps3, Bcl-2, Bax and for their cell life cycle. The results showed that, Tca8113 effective for either single or united medicine all appeared nuclei concentrated and karyomereaccumulated under nucleus membrane, nucleus membrane cremated and mitochondrion swelled, fibril of collagen increased, mirovilli decreased, and death corpuscle formed as the characteristics of death cell change. Inhibition rate of Tca8113 appeared time-dosage dependent relationship. The apototsis rate of Tca8113 in united group (AI 1.27 ±0.38) was higher than single group (AI 0.65 + 0.23) with a remarkable comparing difference (PO.01), and DNA content was lower than single group (P<0.05). Number of cells in S phase rate was decreased and most cells accumulated in Go/Gi. Positive expression for proteins P53, Bcl-2 (0.32 + 0.043, 0.34 + 0.040) was lower than single group (0.47 + 0.023, 0.62 + 0.074) with apparent comparing difference respectively (PO.01). Whereas Bax was much higher than single group (PO.05), Bcl-2/Bax of united group was 0.45 and of single group was 0.94. The experimental results suggest that, death of cells may be the crucial mechanism for chemotherapeutic medicine killing cells of oral cancer. Chemotherapeutic medicine can reduce the expression of proteins P53 and Bcl-2, improve the expression of Protein Bax, in which united chemotherapeutic medicine is more apparent than single chemotherapeutic medicine in inducing apototsis of cells.
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