Patent Description:
Epidermoid Cancer of the Head and Neck is a malignant neoplastic entity originated in the epithelium that covers the mucosa of the aerodigestive tract. Its annual incidence of <NUM>,<NUM> patients places it in sixth positition of the world ranking in terms of more frequent cancers. Of the <NUM>,<NUM> new cases of head and neck tumours (oral cavity, pharynx and larynx) that were detected in the United States in <NUM>, <NUM>% of them corresponded to epidermoid cancer of the head and neck. According to the <NUM> GLOBOCAN Report, Spain is one of the countries with the highest incidence of epidermoid cancer of the head and neck in the entire European continent, proof of this are the <NUM>,<NUM> cases of patients with epidermoid cancer of the head and neck that were diagnosed in <NUM>.

In recent years, the use of saliva as a diagnostic tool or evolutionary follow-up of certain pathologies or diseases, has acquired great relevance in the field of biomedicine. The main advantage of the use of saliva as a diagnostic or follow-up tool is that consists on a noninvasive method, easy to collect, inexpensive, difficult to alter and stable under nonrefrigerated conditions.

The human oral microbiota of which the salivary microbiota is also part comprises the set of microorganisms and pathogens that are components of the oral cavity. Its function is to protect the oral cavity and prevent the development of diseases. Recently, the use of massive sequencing techniques has allowed to study changes in the composition of the oral microbiota of healthy and sick patients. Some of the studies carried out so far, show that sites with oncological character have a lower diversity of species. Currently, the results of the salivary microbiota composition suggest that salivary species such as Capnocytophaga gingivalis, Prevotelle melaninogenica, and Streptococcus Mitis correlate with epidermoid cancer of the head and neck. Dysbiosis between epidermoid head and neck tumour sites and healthy tissues shows a decrease in Actinobacteria and Firmicutes phylo when compared with healthy tissues. However, analysis of the results at genus or species level does not show the same trend.

A link between bacteria in the oral microbioma and oral cavity squamous cell cancer has been described by Ganly et al, where Alloprevotella and Prevotella were found to be enriched in the patients (<NPL>). Similarly, Hsiao et al have shown a link between increased concentrations of oral bacteria, including Prevotella tannerae, renamed as Alloprovotella rava, and oral squamous cell carcinoma. (<NPL>; <NPL>). Prevotella tannerae was described as more prevalent in laryngeal cancer (<NPL>).

The detection of i. Alloprevotella, Prevotella, Campylobacter and Porphyromonas in samples from lung cancer patients and their use to diagnose and stage lung cancer has been described in <CIT>. Furthermore, <CIT> discloses the use of oral microbiome signatures of inter alia Alloprevotella tannerae, Fretibacterium, Prevotella, Porphyromonas, Rothia and Campylobacter in saliva samples from patients and their association with complication in head and neck cancer and guide clinical decision making for a subject in need of radiation therapy and/or chemotherapy for head and neck cancer. The use of such microbiome signatures to diagnose cancers is, however, not described.

Epidermoid cancer of the head and neck is frequently diagnosed in advanced stages of the disease, conferring it a grim prognosis. At present, it seems paradoxical that, with the available means, there are no effective programs for the early detection of this type of tumours. In fact, between the genera proposed in the present invention as possible biomarkers with a predictive and diagnostic character (Rothia, Prevotella, Alloprevotella, Campylobacter, Catonella, Porphylomona and Fretibacterium), Rothia is the only one that has been used as an oral biomarker with clinical indications for carcinoma detection in the oral and oropharyngeal cavity until now [Lim Y, Fukuma N, Totsika M, Kenny L, Morrison M, Punyadeera C: The Performance of an Oral Microbiome Biomarker Panel in Predicting Oral Cavity and Oropharyngeal Cancers. Front Cell Infect My <NUM>, <NUM>].

Thus, we understand that there is still a need to provide useful programs and tools for the early detection of epidermoid cancer of the head and neck.

Throughout the present invention, we analyze the diagnostic and prognostic capacity of the salivary microbiota, to be used as a biomarker for pharyngolaryngeal epidermoid cancer. With this purpose, a clinical study with sample collection at the "Bioithas" clinical research center (Alicante) was carried out. The statistical analysis was performed using the software SPSS © <NUM> and consisted of one descriptive part and another inferential part ("Chi square" test for qualitative variables and "Student's T" for quantitative variables). Spearman's "S" correlation was used for nonparametric samples. Finally, to study the validity of salivary microbiota values as a diagnostic and prognostic proof, ROC curves were used to calculate the most appropriated cut-off points together with their corresponding sensitivity and specificity values.

A total of <NUM> salivary samples corresponding to <NUM> patients and <NUM> healthy controls were included in the study. Among the patients, the average age was <NUM> years (minimum of <NUM> and maximum of <NUM>). Most of them were male (<NUM>%), with a male / female ratio of <NUM> to <NUM>, all patients were at the time of diagnosis in advanced stages of the disease (<NUM>%). The laryngeal location was the most frequently affected (<NUM>%).

Profiles of the salivary microbiota, comparative between cases and controls, and areas under the ROC curve for the main germs involved are described in the figures of the present invention. <FIG> and table <NUM> show the different areas under the curve for each of the genera that showed statistically significant differences between groups in the present study. From this information, is possible to conclude that:.

Therefore, it can be conclude that on the one hand salivary microbiota shows high potential as a prognostic and diagnostic marker for the development of screening programs helping to the early diagnosis of epidermoid cancer of the head and neck in high-risk patients, and on the other hand it has potential to diagnose and predict both evolution and follow-up of patients with epidermoid cancer of the head and neck, being able to complement the known classic diagnostic / prognostic factors.

It is noted that, in the context of the present invention, Alloprevotella genus and, especially, its Alloprevotella rava and Alloprevotella tannerae species, are at lower levels in salivary biological samples of patients with epidermoid cancer of the head and neck than in general population. Furthermore, it is noted that the following sequences SEQ ID NO <NUM> to SEQ ID NO <NUM>, are representative sequences of this genus and, therefore, useful for identification of bacteria belonging to this genus in such samples through a PCR procedure or by means of any sequencing technique, being of special interest the molecular diagnostic techniques by microarray.

Other representative sequences of this genus will be known by the person skilled in the art and they will serve to identify those bacteria belonging to this genus in a saliva sample.

On the other hand, it is noted that, in the context of the present invention, Prevotella genus is at lower levels in salivary biological samples of patients with epidermoid cancer of the head and neck than in general population. Furthermore, it is noted that the following sequences SEQ ID NO <NUM> to SEQ ID NO <NUM>, are representative sequences of this genus and, therefore, useful for the identification of bacteria belonging to this genus in such samples through PCR or any other sequencing technique, including the molecular diagnostic techniques used by DNA microarray.

Furthermore, it is noted that, in the context of the present invention, the Campylobacter genus is at lower levels in salivary biological samples of patients with epidermoid cancer of the head and neck than in general population. Furthermore, it is noted that the following sequences SEQ ID NO <NUM> to SEQ ID NO <NUM>, are representative sequences of this genus and, therefore, useful for the identification of bacteria belonging to this genus in such samples through PCR or any other sequencing technique.

Additionally, it is noted that, in the context of the present invention, the Rothia genus is at increased levels in salivary biological samples of patients with epidermoid cancer of the head and neck compared with general population. Furthermore, it is noted that the following sequences SEQ ID NO <NUM> to SEQ ID NO <NUM>, are representative sequences of this genus and, therefore, useful for identification of bacteria belonging to this genus in such samples through PCR or any other sequencing technique, including the molecular diagnostic techniques used by DNA microarray.

Furthermore, it is noted that, in the context of the present invention, Catonella genus is present at lower levels in salivary biological samples of patients with epidermoid cancer of the head and neck compared with general population. Moreover, it is noted that the following sequences SEQ ID NO <NUM> to SEQ ID NO <NUM>, are representative sequences of this genus and, therefore, useful for identification of bacteria belonging to this genus in such samples through PCR or any other sequencing technique, including the molecular diagnostic techniques used by DNA microarray.

Moreover, it is noted that, in the context of the present invention, the Porphyromona genus is present at lower levels in salivary biological samples of patients with epidermoid cancer of the head and neck compared with general population. Furthermore, it is noted that the following sequences SEQ ID NO <NUM> to SEQ ID NO <NUM>, are representative sequences of this genus and, therefore, useful for identification of bacteria belonging to this genus in such samples through PCR or any other sequencing technique, including the molecular diagnostic techniques used by DNA microarray.

Moreover, it is noted that, in the context of the present invention, the Fretibacterium genus is at lower levels in salivary biological samples of patients with epidermoid cancer of the head and neck than in general population. Furthermore, it is noted that the following sequences SEQ ID NO <NUM> to SEQ ID NO <NUM>, are representative sequences of this genus and, therefore, useful for identification of bacteria belonging to this genus in such samples through PCR or any other sequencing technique, including the molecular diagnostic techniques used by DNA microarray.

Thus, a first aspect of the present invention relates to the in vitro determination and use of the level or concentration of bacteria in a salivary sample, belonging to the genus of Alloprevotella, Prevotella, Campylobacter, Rothia, Catonella, Porphyromona, Fretibacterium, or any combination thereof, for the diagnosis of epidermoid cancer of the oral cavity, of the pharynx and/or the larynx in a patient, or to obtain useful data that enable such diagnosis. Preferably, bacteria belonging to the Alloprevotella genus are Alloprevotella rava and / or Alloprevotella tannerae species. An alternative embodiment of the first aspect of the invention refers to a method for in vitro diagnosis or collection of useful data to Support in such diagnosis, of a subject suspected of resembling epidermoid cancer of the oral cavity, of the pharynx and/or the larynx, which comprises the determination and use as an indicator in a salivary sample obtained from such subject, of the bacteria level or concentration in such sample belonging to the genus of Alloprevotella, Prevotella, Campylobacter, Rothia, Catonella, Porphyromona, Fretibacterium, or any combination thereof, where if the level or concentration in such salivary sample of bacteria belonging to the genus of Alloprevotella, Prevotella, Campylobacter, Rothia, Catonella, Porphyromona, Fretibacterium, or any combination thereof, differs or varies compared with a salivary sample obtained from a healthy subject or a reference value, this is indicative of a subject with epidermoid cancer of the oral cavity, of the pharynx and/or the larynx.

In another preferred embodiment of the first aspect of the invention, the method comprises the use as an indicator in a salivary sample obtained from such subject, of at least the level or concentration in such sample of bacteria belonging to the genus of Alloprevotella, where if the level or concentration in the salivary sample of bacteria belonging to such genus is decreased or significantly lower than in a salivary sample obtained from a healthy subject or compared with a reference value, this is indicative of that such subject shows epidermoid cancer of the oral cavity, of the pharynx and/or the larynx.

In another preferred embodiment of the first aspect of the Invention, the method comprises the determination and use as an indicator in a salivary sample obtained from such subject, of at least the level or concentration in such sample of bacteria belonging to the genus of Prevotella, where if the level or concentration in such salivary sample of bacteria belonging to such genus, is decreased or significantly lower than in a salivary sample obtained from a healthy subject or compared with a reference value, this is indicative of that such subject shows epidermoid cancer of the oral cavity, of the pharynx and/or the larynx.

In another preferred embodiment of the first aspect of the Invention, the method comprises the determination and use as an indicator in a salivary sample obtained from such subject, of at least the level or concentration in such sample of bacteria belonging to the genus of Campylobacter, where if the level or concentration in such salivary sample of bacteria belonging to such genus, is decreased or significantly lower than in a salivary sample obtained from a healthy subject or compared with a reference value, this is indicative of that such subject shows epidermoid cancer of the oral cavity, of the pharynx and/or the larynx.

In another preferred embodiment of the first aspect of the Invention, the method comprises the determination and use as an indicator in a salivary sample obtained from such subject, of at least the level or concentration in such sample of bacteria belonging to the genus of Catonella, where if the level or concentration in such salivary sample of bacteria belonging to such genus, is decreased or significantly lower than in a salivary sample obtained from a healthy subject or compared with a reference value, this is indicative of that such subject shows epidermoid cancer of the oral cavity, of the pharynx and/or the larynx.

In another preferred embodiment of the first aspect of the Invention, the method comprises the determination and use as an indicator in a salivary sample obtained from such subject, of at least the level or concentration in such sample of bacteria belonging to the genus of Porphyromona, where if the level or concentration in such salivary sample of bacteria belonging to such genus, is decreased or significantly lower than in a salivary sample obtained from a healthy subject or compared with a reference value, this is indicative of that such subject shows epidermoid cancer of the oral cavity, of the pharynx and/or the larynx.

In another preferred embodiment of the first aspect of the Invention, the method comprises the determination and use as an indicator in a salivary sample obtained from such subject, of at least the level or concentration in such sample of bacteria belonging to the genus of Fretibacterium, where if the level or concentration in such salivary sample of bacteria belonging to such genus, is decreased or significantly lower than in a salivary sample obtained from a healthy subject or compared with a reference value, this is indicative of that such subject shows epidermoid cancer of the oral cavity, of the pharynx and/or the larynx.

In another preferred embodiment of the first aspect of the Invention, the method comprises the determination and use as an indicator in a salivary sample obtained from such subject, of at least the level or concentration in such sample of bacteria belonging to the genus of Rothia, where if the level or concentration in such salivary sample of bacteria belonging to such genus, is decreased or significantly lower than in a salivary sample obtained from a healthy subject or compared with a reference value, this is indicative of that such subject shows epidermoid cancer of the oral cavity, of the pharynx and/or the larynx.

Epidermoid cancer of the head and neck is considered as the set of malignant tumours produced in the mucosa epithelium of the aerodigestive tracts. This type of cancer represents the <NUM>% of the head and neck cancers and according to their characteristics are classified into three groups:.

It is noted that, the present Invention sufficiently describes the representative nucleotide sequences (i. e SEQ ID No. <NUM> to SEQ No. <NUM>) that allow identifying the presence as well as the concentration of each of the genera mentioned herein in salivary samples.

A second aspect of the present Invention relates to an in vitro method for monitoring the evolution of a subject with epidermoid cancer of the oral cavity, of the pharynx and/or the larynx, which comprises the following Steps:.

where if the level or concentration in such salivary sample of bacteria belonging to the genus of Alloprevotella genus, Prevotella, Campylobacter, Catonella, Porphyromona, Fretibacterium, or any combination thereof, differs or varies from a salivary sample obtained from a healthy subject or with respect to a reference value, this is indicative of the favorable or unfavorable evolution of the subject.

Also described, albeit not part of the claimed invention, is a third aspect relating to an in vitro method for monitoring the evolution of a subject with epidermoid cancer of the oral cavity, of the pharynx and/or the larynx, which comprises the following steps:.

Also described, albeit not part of the claimed invention, is a fourth aspect referring to an in vitro method for predicting the therapeutic response of a patient diagnosed with epidermoid cancer of the oral cavity, of the pharynx and/or the larynx, where such method comprises the following steps:.

Also described, albeit not part of the claimed invention, is a fifth aspect referring to an in vitro method for predicting the therapeutic response of a patient diagnosed with epidermoid cancer of the oral cavity, of the pharynx and/or the larynx, where such method comprises the following steps:.

It is noted that the specific treatment for each type of cancer will depend on the stage in which the disease is found. However, the most common general treatment for this type of pathologies usually is:.

Additionally, it is understood that there is a poor or unfavorable evolution of the subject if the level or concentration in such salivary sample of bacteria belonging to the genus of Alloprevotella, Prevotella, Campylobacter, Catonella, Porphyromona, Fretibacterium, or any combination thereof, is diminished or significantly lower than in a salivary sample obtained from a healthy subject or with respect to a reference value or with respect to the value previously obtained in a salivary sample of the same subject.

Particularly, it is understood that there is an unfavourable response to the treatment if the level or concentration in such salivary sample of bacteria belonging to the genus of Alloprevotella, Prevotella, Campylobacter, Catonella, Porphyromona, Fretibacterium, or any combination thereof, is diminished or significantly lower than in a salivary sample obtained from a healthy subject or with respect to a reference value or with respect to the value previously obtained in a salivary sample of the same subject.

Additionally, it is understood that there is a poor evolution or unfavorable evolution of the subject if the level or concentration in such salivary sample of bacteria belonging to the Rothia genus is also increased or significantly higher than in a salivary sample obtained from a healthy subject or with respect to a reference value or with respect to the value previously obtained in a salivary sample of the same subject.

Additionally, it is understood that there is an unfavorable response to the treatment of the subject if the level or concentration in such salivary sample of bacteria belonging to the Rothia genus is also increased or significantly higher than in a salivary sample obtained from a healthy subject or with respect to a reference value or with respect to the value previously obtained in a salivary sample of the same subject.

Additionally, in the context of the present invention, the reference value is preferably understood as the result of the data of a mathematical algorithm that uses the concentration and / or the total amount of each bacterium belonging to one or more of the genera proposed in the present invention for general population or a healthy subject. The best value for sensitivity and specificity will be proposed automatically using the algorithm. This algorithm will provide values together with the proposed one, as well as changing sensitivity and specificity values providing more information to physicians and allowing them to decide the best test and cut-off value for each patient or specific situation.

In the context of the present invention, it is possible to determine a bacterium belonging to any proposed genera of the salivary sample from such subject, but not limiting to it, through massive sequencing of the saliva genoma obtaining by this way the total number of bacterial sequences in the saliva together with the total number of other bacteria in that saliva sample. Preferably, such determination is performed by PCR or real-time PCR method.

In another preferred embodiment of the first to fifth aspect of the invention or in any of the preferred embodiments of the invention, such bacteria levels or concentration refer to the total amount of bacteria belonging to genus category out of the total bacteria in such sample.

In another preferred embodiment of the first to fifth aspect of the invention or in any of the preferred embodiments of the invention, the levels or concentration of bacteria belonging to the genus of Alloprevotella, Prevotella, Campylobacter, Catonella, Porphyromona, Fretibacterium, or any combination thereof, are determined via an amplification reaction of a nucleic acid preparation derived from such sample using a pair of primers able to amplify one or more representative regions of such genera of bacteria.

Furthermore, in another preferred embodiment of the first to fifth aspect of the invention or in any of the preferred embodiments of the invention, the amplification reaction is carried out by a real-time polymerase chain reaction. Preferably, the detection of the amplification product is accomplished through a fluorescent intercalating agent. More preferably, detection of the amplification product /s is performed by means of a labelled probe, wherein preferably the probe comprises at its <NUM> 'end a reporter pigment and at its <NUM>' end a "quencher" pigment or silencer or buffer.

In a sixth aspect the method for the first to fifth aspect or any of its embodiments, further comprises the storage of the method results on a data carrier, preferably wherein such data carrier is readable by computer.

In a seventh aspect the method of the first to fifth aspect or any of its embodiments, include at least the implementation of the comparative step and optionally the provision of a result as a consequence of such comparison by a computer program.

An eighth aspect, albeit not part of the claimed invention, refers to a kit including one or more primer pairs able to amplify the bacteria belonging to the genus of Alloprevotella, Prevotella, Campylobacter, Catonella, Porphyromona, Fretibacterium, or any combination thereof. Preferably, such kit is used to implement a method for the detection of bacteria from a sample of saliva isolated from a human subject, that comprises the following steps:.

The present invention protects the use of the kit of the eighth aspect of the invention for implementation of the methodology of claim <NUM>.

In connection with this eighth aspect preferably it provides a method for detecting bacteria belonging to Alloprevotella rava and / or Alloprevotella tannerae. In a particular embodiment of this eighth aspect fragments of DNA included or comprised in sequences <NUM> to <NUM> are amplified. In another embodiment of this eighth aspect amplification products, which allow to identify the different species and bacterial groups are detected using probes. In a more preferred embodiment, these probes have between <NUM> to <NUM> nucleotides in length. The primers can be designed by multiple alignment with programs such as CLUSTAL X, which allow the identification of highly conserved regions that serve as a template.

Given the great abundance of PCR inhibitors, such as humic and fulvic acids, heavy metals, heparin, etc. that result in false negatives, and although there are methods that reduce the concentration of these types of molecules, it is recommendable (see <NPL>) PCR tests containing an Internal Amplification Control (IAC). This IAC consist of no more than a fragment of DNA, which is amplified simultaneously together with the target sample, so its absence at the end of the tests is indicative of the presence of factors, that have caused an undesired development of the PCR.

Throughout the description, the term "specific" implies that the primers comprise a nucleotide sequence totally complementary to the genes or gene fragments employed by the present invention.

In summary, the knowledge gained on the composition of the salivary microbiota in patients undergoing treatment along with the development of the diagnostic or prognostic KIT based on this salivary microbiota is of crucial importance, since it would allow the oncology specialist who treats these patients to have data on the probability of a patient showing or not epidermoid cancer of the head and neck in his first visits, in addition to the probability of response to treatment, as well as patient evolution.

The following examples are merely illustrative of the present invention, but they should not be construed as limiting it.

All patients older than <NUM> years with an anatomopathological diagnosis of epidermoid carcinoma of pharyngolaryngeal localization were studied.

Salivary and tissue samples were collected by the Otorhinolaryngology and Molecular Biology service, before signature of the informed consent by all patients who underwent treatment, of benign and malignant head and neck tumours during the period between January <NUM> and December <NUM>, both inclusive. Thereby obtaining an initial total sample of <NUM> patients. Subsequently, between these samples a total of <NUM> patients were chosen and, together with salivary samples from <NUM> healthy volunteers, an analysis of the hypervariable region of the rS16 gene was performed in saliva samples. The results of the sequencing were analyzed in the biomedical research center of Bioithas, located in the scientific park of Alicante. Patients in both groups were selected in order to maintain the homogeneity in their sociodemographic characteristics.

Population included in the final analysis of the data was defined according to the following criteria:.

Biological samples were collected in the Otorhinolaryngology operating room at the time prior to the surgical intervention and in a fasting state of patients.

Saliva samples were collected using lentins placed in the sublingual region for a period of <NUM> minutes and prepared by the researcher. No method was used for the stimulation of salivary production.

All samples were identified and sent to the Research Unit of the Clinical Analysis Service (Laboratory of Molecular Therapy and Cancer Biomarkers), where they were processed. Saliva was centrifuged at <NUM> rpm, <NUM> minutes, the supernatant was aliquotted and frozen at -80ºC until next use.

Contingency tables and "Chi square (X<NUM>)" statistical test were used. Comparison of means with a dichotomous variable was evaluated using "Student's t" statistical test, as long as one variable was quantitative and the other categorical. In cases which the qualitative variable had more than <NUM> categories, the one-way variance analysis (ANOVA) was used.

Different analysis curves were elaborated: ROC curves (acronym of Receiver Operating Characteristic), for the graphic representation of Sensitivity versus <NUM>- Specificity. Optimal cut-off point was determined for each salivary microbiome pattern by searching for the Yoiden index (IY) or maximum sensitivity and specificity point. Area under the curve (AUC) was calculated by the numerical integration of the ROC curves. Concentration with the highest AUC was identified as the strongest predictor for detection of epidermoid cancer of the head and neck. Data were analyzed using SPSS © (version <NUM>) software.

During the study period, a total of <NUM> patients with tumour pathology and <NUM> healthy patients corresponding to the control group were analyzed. Clinical-pathological characteristics of these patients are summarized in Table <NUM> below.

Patients range from <NUM> to <NUM> years old with an average of <NUM> years old and a predominance of males (<NUM>%). <NUM>% of the patients had a smoking habit and <NUM>% had an enolic one. The majority had tumour of laryngeal location (<NUM>%), being the most frequent group the one corresponding to glottic tumours (<NUM>%).

From the obtained salivary samples, those genera with significant differences between groups were analyzed. These results are shown below in table <NUM>.

Additionally, and on the basis of table <NUM> and <FIG>, table <NUM> shows the different areas under the curve for each of the genera showing statistically significant differences between groups in the present study:.

As shown in table <NUM>, <FIG> and <FIG>, both in absolute values and in the presence percentage of Alloprevotella genus in salivary samples and, especially, of Alloprevotella rava and Alloprevotella tannera species, there is a negative correlation between subjects with epidermoid cancer of mouth and pharynx and healthy subjects.

As shown in table <NUM>, <FIG> and <FIG>, both in absolute values and in the presence percentage of Prevotella genus in salivary samples, there is a negative correlation between subjects with epidermoid cancer of the mouth and pharynx and healthy subjects.

As shown in table <NUM>, <FIG> and <FIG>, both in absolute values and in the presence percentage of Campylobacter genus in salivary samples, there is a negative correlation between subjects with epidermoid cancer of mouth and pharynx and healthy subjects.

As shown in table <NUM>, <FIG> and <FIG>, both in absolute values and in the presence percentage of Rothia genus in salivary samples, there is a positive correlation between subjects with epidermoid cancer of mouth and pharynx and healthy subjects.

As shown in table <NUM>, <FIG> and <FIG>, both in absolute values and in the presence percentage of Catonella genus in salivary samples, there is a negative correlation between subjects with epidermoid cancer of the mouth and pharynx and healthy subjects.

As shown in table <NUM>, <FIG> and <FIG>, both in absolute values and in the presence percentage of Porphyromona genus in salivary samples, there is a negative correlation between subjects with epidermoid cancer of the mouth and pharynx and healthy subjects.

As shown in table <NUM>, <FIG> and <FIG>, both in absolute values and in the presence percentage of Fretibacterium genus in salivary samples, there is a negative correlation between subjects with epidermoid cancer of the mouth and pharynx and healthy subjects.

Design of a RNA quantification test (qPCR) by any of the known methods including metagenomics, massive sequencing, qPCR, DNA microarray, and the correlation of these values with the values found by sequencing the hypervariable region Rs16 could be useful for the diagnosis, preferably for the early diagnosis of disease and relapse of epidermoid cancer of the mouth and pharynx.

Claim 1:
Method for the in vitro diagnosis of a subject suspected of having epidermoid cancer of the oral cavity, pharynx and larynx, that comprises the determination and use, as an indicator, in a salivary sample obtained from said subject, of the concentration in such sample of bacteria belonging to the Alloprevotella genus, where if the concentration in such salivary sample of bacteria belonging to Alloprevotella is significantly lower than in a salivary sample obtained from a healthy subject or with respect to a reference value, this is indicative that such subject has epidermoid cancer of the oral cavity, pharynx and larynx.