Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.

Example Input: Abstract: Injection of homologous DNA sequences into nuclei of cultured mammalian cells induces mutations in the cognate chromosomal gene. It appears that these mutations result from incorrect repair of a heteroduplex formed between the introduced and the chromosomal sequence. This phenomenon is termed 'heteroduplex induced mutagenesis'. The high frequency of these events suggests that this method may prove useful for introducing mutations into specific mammalian genes.
Example Output: Introduction of homologous DNA sequences into mammalian cells induces mutations in the cognate gene.

Example Input: Abstract: Twenty-seven patients with squamous cell carcinoma of the mobile tongue and floor of the mouth were treated with external beam and interstitial radiation. Good prognostic factors were T1N0, T2N0, superficial tumors, tumor shrinkage by 75% with external beam, and no apparent tumor clinically 2 months after treatment. On the other hand, T3N0, T1-3N1, and deeply necrotic tumors had a poor prognosis. We recommend using a flexible afterloading system to implant the initial local tumor volume (not just the residual nidus) that does not exceed 45 cm3. The minimum (reference) dose was prescribed to a surface 1/2 cm beyond the most peripheral rim of radioactive sources. For acceptable local control and complication rates, our suggested minimum (reference) doses are less than or equal to 7,500 rads for T1 (or a time-dose-fractionation [TDF] of 131-140), less than or equal to 8,000 rads for T2 (TDF of 131-140), and probably less than 8,500 rads for T3 (TDF of less than or equal to 150). These guidelines should be considered preliminary.
Example Output: Proposed method to study the factors affecting local control with combined external beam and interstitial implantation of mobile tongue and floor of mouth.

Example Input: Abstract: Separate antisera were raised against keratocyst, dentigerous cyst, and radicular cyst fluids and used to analyse a range of fluids from cysts of known type. Samples were subjected to crossed immunoelectrophoresis into homologous antiserum through an intermediate gel containing antibody to whole human serum to screen out serum derived components. A major antigen, designated X, which seems to be of epithelial origin but is not a keratin, was identified in keratocyst fluids. X resolves as two bands on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) with molecular weights of 81 K and 89 K and its major antigenic epitope is associated with disulphide bonds. Of the cysts studied to date, antigen X has been found consistently and exclusively in fluids from keratocysts; its presence and detection is independent of total soluble protein concentration and thus offers real potential as a reliable marker for preoperative diagnosis.
Example Output:
Recognition of protein apparently specific to odontogenic keratocyst fluids.